As filed with the Securities and Exchange Commission on May 21, 2004.

                                                     Registration No. 333-115393

               UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                             -------------------

                                AMENDMENT NO. 1
                                       TO
                                    FORM S-3

           REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                             -------------------

                           IRIS INTERNATIONAL, INC.
            (Exact name of registrant as specified in its charter)

                             -------------------

                    Delaware                                   95-2579751
                    --------                                   ----------
(State of other jurisdiction of incorporation                (I.R.S. Employer
                or organization)                            Identification No.)

                                9172 ETON AVENUE
                          CHATSWORTH, CALIFORNIA 91311
                                 (818) 709-1244
    (Address, Including Zip Code, and Telephone Number, Including Area Code,
                 of Registrant's Principal Executive Offices)

                             -------------------


Name and address of agent for service:         Copies of communications sent to:
-------------------------------------          ---------------------------------
      MARTIN G. PARAVATO                            JOSEPH E. NIDA, ESQ.
   CHIEF FINANCIAL OFFICER                 SHEPPARD MULLIN RICHTER & HAMPTON LLP
   IRIS INTERNATIONAL, INC.                         800 ANACAPA STREET
       9172 ETON AVENUE                           SANTA BARBARA, CA 93101
 CHATSWORTH, CALIFORNIA 91311

      Approximate date of commencement of proposed sale to the public: FROM TIME
   TO TIME AFTER THE EFFECTIVE DATE OF THIS REGISTRATION STATEMENT.

      If the only  securities  being  registered  on this form are being offered
   pursuant  to  dividend  or  interest  reinvestment  plans,  please  check the
   following box.  |_|

      If any of the securities  being  registered on this Form are to be offered
   on a delayed or continuous  basis  pursuant to Rule 415 under the  Securities
   Act of 1933,  other than securities  offered only in connection with dividend
   or interest reinvestment plans, check the following box.  |X|

      If this Form is filed to register  additional  securities  for an offering
   pursuant to Rule 462(b) under the Securities  Act, please check the following
   box and list the Securities Act registration  statement number of the earlier
   effective registration statement for the same offering. |_| ___________

      If this Form is a  post-effective  amendment filed pursuant to Rule 462(c)
   under  the  Securities  Act,  please  check  the  following  box and list the
   Securities  Act  registration  statement  number  of  the  earlier  effective
   registration statement for the same offering. |_|___________

      If delivery of the prospectus is expected to be made pursuant to Rule 434,
   please check the following box.  |_|








                         CALCULATION OF REGISTRATION FEE


-------------------------------------------------------------------------------------------------------------------------
                                                   Proposed maximum
   Title of each class of      Amount to be       offering price per         Proposed maximum                Amount of
securities to be registered)    registered               share           aggregate offering price       registration fee
-------------------------------------------------------------------------------------------------------------------------
                                                                                               
Common Stock, par value        2,571,975 shares(2)      $7.08                  $18,209,583(1)              $2,307.15
$0.01 per share
-------------------------------------------------------------------------------------------------------------------------



(1)   Estimated  solely for the  purpose of  calculating  the  registration  fee
      pursuant  to Rule 457(c)  under the  Securities  Act of 1933,  as amended,
      based on a per  share  price of  $7.08,  the  average  of the high and low
      reported  sales  prices of the  Registrant's  common  stock on the  Nasdaq
      National Market on May 4, 2004.

(2)   Includes  441,975  shares  of  common   stock  issuable  upon  exercise of
      warrants sold in the private placement transaction on April 22, 2004.






   The  Registrant  hereby  amends this  Registration  Statement on such date or
dates as may be necessary to delay its effective date until the Registrant shall
file a further  amendment  which  specifically  states  that  this  Registration
Statement shall  thereafter  become effective in accordance with section 8(a) of
the  Securities  Act of 1933,  as amended (the  "Securities  Act") or until this
Registration Statement shall become effective on such date as the Securities and
Exchange  Commission  (the "SEC"),  acting  pursuant to said Section  8(a),  may
determine.


                               [INSERT IRIS LOGO]



                            IRIS International, Inc.

                                2,571,975 Shares

                                  Common Stock

                                ($0.01 Par Value)

                                --------------

      This  prospectus  relates to the  disposition  of 2,571,975  shares of our
common  stock  which  may be  disposed  of,  from time to time,  by the  selling
stockholders  listed  in  the  section  of  this  prospectus  entitled  "Selling
Stockholders," or other transferees,  pledges, donees or successors-in-interest.
The shares offered by this  prospectus,  include  441,975 shares of common stock
issuable  upon  exercise of  warrants.  The shares were  initially  sold and the
warrants  were  initially  issued  to  the  selling  stockholders  in a  private
placement  transaction  on April 22, 2004.  While we will not receive any of the
proceeds  from the sale of the  2,571,975  shares  being  offered by the selling
stockholders  hereunder,  we will  receive  up to  $2,492,100  if and  when  the
warrants are exercised.

      Our common stock is quoted on the Nasdaq  National Market under the symbol
"IRIS." On May 10, 2004,  the last  reported  sale price for our common stock on
the Nasdaq National Market was $7.52 per share.

                                --------------

      INVESTMENT  IN OUR COMMON  STOCK  INVOLVES A HIGH  DEGREE OF RISK.  PLEASE
CAREFULLY CONSIDER THE "RISK FACTORS" BEGINNING ON PAGE 4 OF THIS PROSPECTUS.

                               --------------

      NEITHER THE  SECURITIES AND EXCHANGE  COMMISSION NOR ANY STATE  SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS  IS TRUTHFUL OR  COMPLETE.  ANY  REPRESENTATION  TO THE CONTRARY IS A
CRIMINAL OFFENSE.
                                --------------

                   The date of this prospectus is May 21, 2004





                                TABLE OF CONTENTS

                                                        Page
                                                        ----

                  Prospectus Summary.......................2
                  Risk Factors.............................4
                  Use of Proceeds.........................12
                  Selling Stockholders....................12
                  Plan of Distribution....................15
                  Legal Matters...........................17
                  Experts.................................17
                  Where You Can Find More Information.....17
                  Information Incorporated by Reference...18



                   INFORMATION CONTAINED IN THIS PROSPECTUS

      YOU SHOULD  RELY ONLY ON THE  INFORMATION  CONTAINED  OR  INCORPORATED  BY
REFERENCE IN THIS PROSPECTUS.  WE HAVE NOT AUTHORIZED ANYONE ELSE TO PROVIDE YOU
WITH DIFFERENT INFORMATION.  THIS DOCUMENT MAY BE USED ONLY WHERE IT IS LEGAL TO
SELL THESE  SECURITIES.  THE INFORMATION IN THIS PROSPECTUS MAY ONLY BE ACCURATE
AS OF THE DATE OF THIS PROSPECTUS.

                                --------------

      Unless the context otherwise  requires,  the terms "we," "our," "us," "our
company," and "IRIS" refer to IRIS International, Inc. and its subsidiaries.




              SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

      Statements  in  this  prospectus  and in  the  documents  incorporated  by
reference in this  prospectus  that are not  statements of  historical  fact are
forward-looking  statements.  These  statements  relate  to  our  future  plans,
objectives,  expectations  and  intentions.  You may  generally  identify  these
statements by the use of words such as "expect,"  "anticipate," "intend," "plan"
and similar expressions.

      You should not place undue reliance on our forward-looking statements. Our
actual  results  could  differ   materially  from  those  anticipated  in  these
forward-looking  statements as a result of numerous risks and uncertainties that
are beyond  our  control,  including  those we  discuss  in "Risk  Factors"  and
elsewhere in this  prospectus and in the documents  incorporated by reference in
this prospectus.  The information in this prospectus  speaks only as of the date
of this prospectus and the information  incorporated  herein by reference speaks
only as of its  date.  You  should  not rely on these  statements  without  also
considering the risks and uncertainties associated with these statements and our
business.


                                      1



                               PROSPECTUS SUMMARY

      THIS  SUMMARY   HIGHLIGHTS   INFORMATION   CONTAINED   ELSEWHERE  IN  THIS
PROSPECTUS.  BECAUSE  THIS IS ONLY A  SUMMARY,  IT DOES NOT  CONTAIN  ALL OF THE
INFORMATION  THAT YOU SHOULD  CONSIDER  BEFORE  INVESTING  IN OUR COMMON  STOCK.
THEREFORE,  YOU SHOULD READ  CAREFULLY  AND  CONSIDER  THIS  ENTIRE  PROSPECTUS,
INCLUDING THE "RISK  FACTORS"  SECTION AND THE  INFORMATION  WE  INCORPORATE  BY
REFERENCE, BEFORE INVESTING IN OUR COMMON STOCK.

IRIS INTERNATIONAL, INC. (FORMERLY, INTERNATIONAL REMOTE IMAGING SYSTEMS,
INC.)

      IRIS  operates  through its Iris  Diagnostics  division and its  StatSpin,
Inc.,  Advanced Digital Imaging  Research,  LLC (ADIR) and IRIS Global Networks,
Inc.  subsidiaries.  IRIS's operating units design,  develop,  manufacture,  and
market  patented and  proprietary  image-based in vitro  diagnostic  systems for
automating  microscopic  urinalysis,   and  innovative  centrifuges  for  blood,
cytology, and urinalysis.  The divisions and subsidiaries of IRIS are summarized
below.

      Iris Diagnostics is a leader in automated  urinalysis  technology with its
workstations installed in major medical institutions  throughout the world. Iris
Diagnostics  manufactures the only clinical analyzers using real-time video flow
imaging,  displaying  microscopic  images on a video  screen.  The  systems  are
operated by touch screen interfaces  pioneered by IRIS for use in urinalysis and
microscopic  analysis of body fluids.  IRIS's  imaging  systems use patented and
proprietary  Automated  Intelligent  Microscopy  (AIM) technology for automating
microscopic  procedures,  enabling clinical laboratory  technologists to rapidly
and  efficiently  analyze and  process  specimens  automatically,  significantly
reducing the costly and  time-consuming  manual steps  required for  microscopic
analysis.

      The StatSpin(R) subsidiary, acquired in 1996 by IRIS, excels as a maker of
innovative  centrifuges  and blood  analysis  products.  Forty  thousand  of its
benchtop  centrifuge systems have been sold to date. Major medical  institutions
worldwide,  along with thousands of smaller hospitals,  commercial laboratories,
clinics,  doctors'  offices,  veterinary  labs  and  research  institutions  use
StatSpin's products.  StatSpin  manufactures the world's fastest blood separator
(30 seconds). Its bench top centrifuges are dedicated to applications for manual
specimen  preparation  in  coagulation,  cytology,  hematology  and  urinalysis.
StatSpin has been  providing  centrifuges  to the  veterinary  market  through a
company  which  provides  sample and analysis  systems and  recently  passed the
13,000th centrifuge shipped to this market.

      Advanced  Digital  Imaging  Research  (ADIR) is a research and development
organization specializing in digital imaging software and algorithm development.
Located in the Houston,  Texas area, ADIR conducts R&D projects sponsored by the
National Institutes of Health, NASA, and corporate clients. ADIR has a number of
ongoing  NIH-sponsored  research projects being conducted in collaboration  with
medical  researchers  around the United States.  New technology  developed under
these  projects  will be made  available to IRIS and other client  companies for
commercialization. ADIR is expanding the scope of its research activities beyond
cytogenetics,  to  include  projects  of  interest  to IRIS and other  corporate
clients.  ADIR also plans to  commercialize  non-company  related  technology by
means of patents and licensing agreements.

      In June 2003,  we  established  a European  subsidiary  called IRIS Global
Networks,  Inc., in Novara, Italy, just outside of Milan. This office will serve
as the base for Sales and Service support for the expanding distribution network
being  established for our recently  launched iQ200  Automated Urine  Microscopy
Analyzer.  With distribution  agreements  covering multiple countries in Europe,
Africa and the Middle East, the  establishment  of this subsidiary  gives us the
needed infrastructure to support those distributors.


                                       2


      We are a Delaware  corporation.  Our executive offices are located at 9172
Eton Avenue,  Chatsworth,  California,  91311, and our telephone number is (818)
709-1244. Our website address is www.proiris.com. The information on our website
is not a part of this prospectus.




































                                       3


                                  RISK FACTORS

      AN  INVESTMENT  IN OUR COMMON  STOCK  INVOLVES A HIGH  DEGREE OF RISK.  IN
ADDITION  TO THE  OTHER  INFORMATION  CONTAINED  IN THIS  PROSPECTUS  AND IN THE
DOCUMENTS  THAT WE INCORPORATE  BY REFERENCE  INTO THIS  PROSPECTUS,  YOU SHOULD
CAREFULLY  CONSIDER THE FOLLOWING RISKS AND UNCERTAINTIES  BEFORE PURCHASING OUR
COMMON  STOCK.  IF ANY OF  THESE  RISKS  OR  UNCERTAINTIES  WERE TO  OCCUR,  OUR
BUSINESS,  FINANCIAL  CONDITION AND OPERATING RESULTS COULD SUFFER SERIOUS HARM.
IN THAT CASE,  THE TRADING PRICE OF OUR COMMON STOCK COULD DECLINE AND YOU COULD
LOSE ALL OR PART OF YOUR INVESTMENT.  SEE ALSO, "SPECIAL NOTE ON FORWARD-LOOKING
STATEMENTS."

RISKS RELATED TO OUR BUSINESS

      OUR SUCCESS DEPENDS LARGELY ON THE ACCEPTANCE OF OUR NEW IQ200
OPERATING PLATFORM.

     Our current  strategy  assumes that our iQ200  operating  platform  will be
adopted by a large  number of  end-users.  We have  invested,  and  continue  to
invest, a substantial  amount of our resources in promotion and marketing of the
iQ200 operating platform in order to increase its market penetration, expand its
sales into new geographic  areas and enhance and expand its system  features.  A
failure of our iQ200  operating  platform to achieve and maintain a  significant
market  presence,  or the failure to  successfully  implement  our promotion and
marketing  strategy,  will  have a  material  adverse  effect  on our  financial
condition and results of operations.

      WE FACE INTENSE COMPETITION AND OUR FAILURE TO COMPETE EFFECTIVELY,
PARTICULARLY AGAINST LARGER, MORE ESTABLISHED COMPANIES WILL CAUSE OUR
BUSINESS TO SUFFER.

      The healthcare industry is highly competitive. We compete in this industry
based  primarily  on  product  performance,  service  and  price.  Many  of  our
competitors have substantially greater financial,  technical and human resources
than we do, and may also have  substantially  greater  experience  in developing
products,  obtaining  regulatory  approvals and  manufacturing and marketing and
distribution.  As a result, they may be better able to compete for market share,
even in areas in which our products may be superior.  Further,  our  competitive
position  could be  harmed by the  establishment  of  patent  protection  by our
competitors or other companies.  The existing competitors or other companies may
succeed in  developing  technologies  and  products  that are more  effective or
affordable  than those being developed by us or that would render our technology
and  products  less  competitive  or obsolete.  If we are unable to  effectively
compete in our market,  our financial  condition and results of operations  will
materially suffer.

      WE HAVE  HAD A  HISTORY  OF  DECLINING  PROFITABILITY  AND  RECORDED  AN
OPERATING LOSS IN 2003.  WE MAY INCUR LOSSES IN THE FUTURE.

      We have  incurred  significant  losses  since  our  inception  and,  as of
December 31, 2003, we had accumulated a deficit of approximately  $25.0 million.
We may not achieve profitability in the future and further losses may arise. Our
ability to  achieve  profitable  operations  in the  future  will  depend on our
ability to sell our products at sufficient  volumes and with sufficient  margins
to be  profitable.  If we are unable to do so, we will not be profitable and our
financial condition and results of operations will suffer.

      OUR QUARTERLY SALES AND OPERATING RESULTS MAY FLUCTUATE IN FUTURE
PERIODS, AND IF WE FAIL TO MEET EXPECTATIONS THE PRICE OF OUR COMMON STOCK
MAY DECLINE.

      Our quarterly sales and operating results have fluctuated significantly in
the past and are likely to do so in the future due to a number of factors,  many
of which are not within our control. If our quarterly sales or operating results


                                       4


fall below the  expectations of investors or securities  analysts,  the price of
our common stock could decline substantially. Factors that might cause quarterly
fluctuations in our sales and operating results include the following:

      o variation in demand for our products, including seasonality;

      o our ability to develop,  introduce, market and gain market acceptance of
        new products and product enhancements in a timely manner;

      o our ability to manage inventories, accounts receivable and cash flows;

      o our ability to control costs;

      o the size, timing,  rescheduling or cancellation of orders from consumers
        and distributors; and

      o our  ability  to  forecast  future  sales  and  operating  results  and
        subsequently attain them.

      The amount of  expenses we incur  depends,  in part,  on our  expectations
regarding  future  sales.  In  particular,   we  expect  to  continue  incurring
substantial  expenses  relating to the  marketing and promotion of our products.
Since many of our costs are fixed in the short term,  if we have a shortfall  in
sales,  we may be unable to reduce expenses  quickly enough to avoid losses.  If
this  occurs,  we will not be  profitable.  Accordingly,  you should not rely on
quarter-to-quarter  comparisons of our operating results as an indication of our
future performance.

      OUR SUCCESS DEPENDS LARGELY ON SALES OF LABORATORY INSTRUMENTS AND
RELATED SALES OF CONSUMABLES AND SERVICE CONTRACTS.

      Historically, we derived most of our revenues from the sale of consumables
and  service  revenue  and to a  lesser  extent  from  the  sale  of  urinalysis
workstations.  Modest declines in unit sales of urinalysis workstations or gross
margins for this  product line could  diminish  our  revenues  and  profits.  In
addition,  because our  installed  base of  workstations  utilize a large annual
volume of consumables and produce service revenue,  any decline in our installed
base will diminish revenues and profits even further.

      WE RELY ON INDEPENDENT AND SOME SINGLE-SOURCE SUPPLIERS FOR KEY
COMPONENTS OF OUR INSTRUMENTS.  ANY DELAY OR DISRUPTION IN THE SUPPLY OF
COMPONENTS MAY PREVENT US FROM SELLING OUR PRODUCTS AND NEGATIVELY IMPACT OUR
OPERATIONS.

      Certain of our components are obtained from outside  vendors,  the loss or
breakdown of our  relationships  with these outside  vendors could subject us to
substantial delays in the delivery of our products to our customers. Furthermore
certain key components of our  instruments  are  manufactured  by  single-source
suppliers. For example, ARKRAY is the single-source supplier for our new line of
urine  chemistry  analyzers  and related  consumable  products  and spare parts.
ARKRAY's  AX-4280  Automated  Urine Chemistry  Analyzer  combines with our iQ200
Automated Urine Microscopy Analyzer to constitute our iQ200 system. If we are no
longer able to sell ARKRAY's chemistry analyzer, we will have to replace it with
a  chemistry  analyzer  from  another  source,  which could  interrupt  domestic
deliveries  of the iQ200  system  and have an adverse  effect on our  results of
operations.  Roche Diagnostics is the single-source supplier for our proprietary
CHEMSTRIP/ IRIStrip urine test strips and related urine test strip readers, both
used  in the  Model  500  and  939UDx  urinalysis  workstations.  Because  these
suppliers  are  the  only  vendors  with  which  we  have a  relationship  for a
particular  component,  we  may be  unable  to  sell  products  if one of  these
suppliers  becomes  unwilling  or  unable  to  deliver  components  meeting  our
specifications.  Our inability to sell products to meet delivery schedules could
have a material  adverse effect on our reputation in the industry as well as our
financial condition and results of operations.

                                       5



      ONE OF OUR SINGLE-SOURCE SUPPLIERS HAS TERMINATED ITS AGREEMENT WITH US.

      Roche  Diagnostics  has exercised  its right to terminate  the  agreements
relating  to the supply of test  strips and  related  urine test strip  readers.
Roche  will  continue  to supply  test  strips  and  replacement  readers to our
installed  base of  workstations  for  six  years  after  termination  of  these
contracts,  or until 2009. The failure to  successfully  and timely complete the
phase out of their  strips and readers  with the  introduction  of our new iQ200
analyzers would have a material  adverse effect on our instrument  sales and the
revenue growth for system supplies and service.

      WE MAY NEED ADDITIONAL CAPITAL IN THE FUTURE.  IF ADDITIONAL CAPITAL IS
NOT AVAILABLE, WE MAY HAVE TO CURTAIL OR CEASE OPERATIONS.

      We have limited capital and will require  substantial capital resources to
execute our business strategy.

      Any equity financings may be dilutive to our existing stockholders and may
involve the issuance of securities  that have rights,  preferences or privileges
senior to those of our current stockholders. A debt financing, if available, may
involve  restrictive  covenants on our business that could limit our operational
and financial  flexibility,  and the amount of debt incurred  could make us more
vulnerable  to economic  downturns  or  operational  difficulties  and limit our
ability to compete. Furthermore, financing may not be available when needed and,
if available, may not be on terms acceptable to us.

      WE OPERATE IN A CONSOLIDATING INDUSTRY WHICH CREATES BARRIERS TO OUR
MARKET PENETRATION.

      The  healthcare  industry  in  recent  years  has  been  characterized  by
consolidation.  Large hospital chains and groups of affiliated  hospitals prefer
to negotiate  comprehensive  supply  contracts  for all of their supply needs at
once.  Large  suppliers  can often  equip an entire  laboratory  and offer these
hospital  chains  and  groups  one-stop  shopping  for  laboratory  instruments,
supplies and service.  Larger  suppliers also typically  offer annual rebates to
their  customers  based on the  customer's  total  volume of  business  with the
supplier.  The  convenience  and rebates  offered by these large  suppliers  are
administrative and financial incentives that we do not offer our customers.  Our
plans for further market  penetration  in the  urinalysis  market will depend in
part on our  ability  to  overcome  these and any new  barriers  resulting  from
continued consolidation in the healthcare industry. The failure to overcome such
barriers  could have a material  adverse  effect on our  financial  condition or
results of operations.

      BUSINESS INTERRUPTIONS COULD ADVERSELY AFFECT OUR BUSINESS.

      Products for Iris  Diagnostics  and StatSpin are  manufactured in a single
facility for each division and are  vulnerable to  interruption  in the event of
war, terrorism, fire, earthquake, power loss, floods, telecommunications failure
and other  events  beyond our  control.  If our  facilities  were  significantly
damaged or destroyed by any cause, we would experience  delays in locating a new
facility and  equipment and  qualifying  the new facility with the Food and Drug
Administration  ("FDA"). As a result, our results would suffer. In addition,  we
may not carry  adequate  business  interruption  insurance to  compensate us for
losses  that  may  occur  and any  losses  or  damages  incurred  by us could be
substantial.

      IF WE ARE UNABLE TO MANAGE OUR GROWTH, OUR RESULTS COULD SUFFER.

      We  have  been  experiencing  significant  growth  in  the  scope  of  our
operations. This growth has placed significant demands on our management as well
as  operational  resources.  In order to achieve  our  business  objectives,  we
anticipate that we will need to continue to grow. If this growth occurs, it will

                                       6


continue  to place  additional  significant  demands on our  management  and our
operational resources,  and will require that we continue to develop and improve
our  operational,  financial  and other  internal  controls both in the U.S. and
internationally.  In  particular,  our  growth  rate  has  increased  and  if it
continues to do so, we will face many  challenges  in  implementing  appropriate
control systems, expanding our sales and marketing infrastructure  capabilities,
providing  adequate training and supervision to maintain high quality standards,
and preserving our cultural  values.  Currently,  the main challenge  associated
with our  growth  has been  cash flow  management.  Our  inability  to scale our
business  appropriately  or otherwise  adopt to growth would cause our business,
financial condition and results of operations to suffer.

      OUR SUCCESS DEPENDS ON OUR ABILITY TO ATTRACT, RETAIN AND MOTIVATE
MANAGEMENT AND OTHER SKILLED EMPLOYEES.

      Our success depends in significant part upon the continued services of key
management and skilled personnel. Competition for qualified personnel is intense
and there are a limited  number of people with  knowledge of, and experience in,
our  industry.  We do not  have  employment  agreements  with  most  of our  key
employees  or   maintain  life  insurance  policies  on  them.  The  loss of key
personnel, especially without advance notice, or our inability to hire or retain
qualified  personnel,  could have a material  adverse  effect on our  instrument
sales and our ability to maintain our  technological  edge. We cannot  guarantee
that we will continue to retain our key  management  and skilled  personnel,  or
that we will be able to attract,  assimilate  and retain other highly  qualified
personnel in the future.

      ANY FAILURE TO SUCCESSFULLY INTRODUCE OUR FUTURE PRODUCTS AND SYSTEMS
INTO THE MARKET COULD ADVERSELY AFFECT OUR BUSINESS.

      The  commercial  success of our future  products and systems  depends upon
their  acceptance  by the medical  community.  Our future  product plans include
capital-intensive  laboratory  instruments.  There is often market resistance to
products that require significant  capital  expenditures or which eliminate jobs
through automation.  We have no assurance that the market will accept our future
products and systems, or that sales of our future products and systems will grow
at the rates expected by our management.

      OUR SALES IN INTERNATIONAL MARKETS ARE SUBJECT TO A VARIETY OF LAWS AND
POLITICAL AND ECONOMIC RISKS THAT MAY ADVERSELY IMPACT OUR SALES AND RESULTS
OF OPERATIONS IN CERTAIN REGIONS.

      Our ability to  capitalize on growth in new  international  markets and to
maintain the current level of operations in our existing  international  markets
is  subject to risks  associated  with  international  sales  operations.  These
include:

      o  changes  in  currency   exchange   rates  which  impact  the  price  to
         international consumers;

      o  the  burdens  of  complying  with   a   variety  of  foreign  laws  and
         regulations;

      o  unexpected changes in regulatory requirements; and

      o  the difficulties  associated  with  promoting  products  in  unfamiliar
         cultures.

   We are also subject to general  political,  economic and regulatory  risks in
connection  with our  international  sales  operations,  including:

      o political instability;

      o changes in diplomatic and trade relationships;

      o general economic fluctuations in specific countries or markets; and

      o changes in regulatory schemes.

                                       7


      Any of the  abovementioned  factors could  adversely  affect our sales and
results of operations in international markets.

      WE DEPEND ON INDEPENDENT DISTRIBUTORS TO SELL OUR PRODUCTS IN
INTERNATIONAL MARKETS.

      We  sell  our  products  in  international   markets  through  independent
distributors.  These  distributors  may not command the  necessary  resources to
effectively market and sell our products.  If a distributor fails to meet annual
sales goals,  it may be difficult and costly to locate an acceptable  substitute
distributor.  If  a  change  in  our  distributors  becomes  necessary,  we  may
experience  increased  costs, as well as substantial  disruption and a resulting
loss of sales.

      IF WE FAIL TO MEET CHANGING DEMANDS OF TECHNOLOGY, WE MAY NOT CONTINUE
TO BE ABLE TO COMPETE SUCCESSFULLY WITH OUR COMPETITORS.

      The  market  for our  products  and  systems  is  characterized  by  rapid
technological  advances,  changes in customer  requirements,  and  frequent  new
product  introductions  and  enhancements.  Our future success  depends upon our
ability  to   introduce   new  products   that  keep  pace  with   technological
developments,  enhance  current  product lines and respond to evolving  customer
requirements.  Our failure to meet these  demands  could result in a loss of our
market  share and  competitiveness  and could harm our  revenues  and results of
operations.

      CHANGES IN GOVERNMENT REGULATION OF THE HEALTHCARE INDUSTRY COULD
ADVERSELY AFFECT OUR BUSINESS.

      Federal and state  legislative  proposals are  periodically  introduced or
proposed that would affect major changes in the healthcare  system,  nationally,
at the state level or both. Future  legislation,  regulation or payment policies
of Medicare,  Medicaid,  private  health  insurance  plans,  health  maintenance
organizations and other third-party payors could adversely affect the demand for
our  current  or future  products  and our  ability  to sell our  products  on a
profitable basis.  Moreover,  healthcare legislation is an area of extensive and
dynamic  change,  and  we  cannot  predict  future  legislative  changes  in the
healthcare field or their impact on our industry or our business. Any impairment
of our ability to market our products  could have a material  adverse  effect on
our financial condition and results of operations.

      SINCE WE OPERATE IN THE MEDICAL TECHNOLOGY INDUSTRY, OUR PRODUCTS ARE
SUBJECT TO GOVERNMENT REGULATION THAT COULD IMPAIR OUR OPERATIONS.

      Most of our products are subject to stringent government regulation in the
United States and other countries.  These  regulatory  processes can be lengthy,
expensive  and  uncertain.   Additionally,   securing  necessary  clearances  or
approvals  may require  the  submission  of  extensive  official  data and other
supporting information. Our failure to comply with applicable requirements could
result in fines,  recall or seizure of products,  total or partial suspension of
production,  withdrawal of existing product approvals or clearances,  refusal to
approve or clear new applications or notices, or criminal prosecution. If any of
these events were to occur,  they could harm our  business.  Changes in existing
federal,  state or foreign  laws or  regulations,  or in the  interpretation  or
enforcement of these laws, could have a material adverse effect on our business.

      WE ARE SUBJECT TO CURRENCY FLUCTUATIONS.

      We are exposed to certain  foreign  currency  risks in the  importation of
goods from Japan. The new line of urine chemistry analyzers, some assemblies for
our iQ200  platform and related  consumables  strips and spare parts are sourced
from  ARKRAY,  a  supplier  located in Kyoto,  Japan.  Our  purchases  from this
supplier  are  denominated  in  Japanese  Yen.  These  components   represent  a
significant  portion of our material  costs.  Fluctuations  in the U.S.  Dollar/

                                       8


Japanese  Yen  exchange  rate  would  result  in  increased  costs  for  our key
components.  Any such  increases  would  reduce our gross  margins  and would be
likely to result in a material  adverse  effect on our  revenues  and  financial
condition.  Similarly, we are also exposed to currency fluctuations with respect
to the  exportation  of our  products.  Although  our  international  sales  are
denominated in U.S.  Dollars,  we have agreements with our distributors to share
fluctuations outside of a certain range in such exchange rates. Accordingly, any
fluctuation in the exchange rate between the U.S. Dollar and the currency of the
country with which we are exporting products would also reduce our gross margins
and would be likely to result  in a  material  adverse  effect on our  financial
condition and results of operations.

      OUR COPYRIGHTS AND TRADEMARKS MAY NOT BE ENFORCEABLE.

      We claim copyrights in our software and the ways in which it assembles and
displays  images.  We also claim trademark rights in the United States and other
foreign  countries.  However,  we can make no assurance  that we will be able to
obtain enforceable copyright and trademark  protection,  or that this protection
will provide us a significant commercial advantage.

      OUR PRODUCTS COULD INFRINGE ON THE INTELLECTUAL PROPERTY RIGHTS OF
OTHERS.

      Given the complete factual and legal issues  associated with  intellectual
property rights,  there can be no assurance that our current and future products
do not or will not  infringe  the  intellectual  property  rights of  others.  A
determination that such infringement exists or even a claim that it exists could
involve us in costly  litigation  and have an adverse effect on our business and
financial condition.

      WE MAY BE SUBJECT TO LITIGATION REGARDING OUR PATENT AND OTHER
INTELLECTUAL PROPERTY RIGHTS.

      Offensive or defensive  litigation regarding patent and other intellectual
property rights could be time-consuming and expensive. Additionally,  litigation
could demand significant  attention from our technical and management personnel.
Any change in our ability to protect and maintain our  proprietary  rights could
materially  and  adversely  affect  our  financial   condition  and  results  of
operations.

      ANY FAILURE OR INABILITY TO PROTECT OUR TECHNOLOGY AND CONFIDENTIAL
INFORMATION COULD ADVERSELY AFFECT OUR BUSINESS.

      PATENTS.  Our commercial success depends in part on our ability to protect
and maintain our Automated Intelligent Microscopy (or AIM) and other proprietary
technology.   We  have  received   patents  with  respect  to  portions  of  the
technologies of AIM. However,  ownership of technology  patents may not insulate
us from potentially damaging competition. Patent litigation relating to clinical
laboratory instrumentation patents (like the ones we own) often involves complex
legal and factual  questions.  Therefore,  we can make no assurance  that claims
under  patents   currently   held  by  us,  or  our  pending  or  future  patent
applications,  will be sufficiently  broad to adequately protect what we believe
to be our proprietary rights. Additionally,  one or more of our patents could be
circumvented by a competitor.

      TRADE  SECRETS.   We  have  trade  secrets,   unpatented   technology  and
proprietary knowledge related to the sale, promotion, operation, development and
manufacturing  of  our  products.   We  generally  enter  into   confidentiality
agreements with our employees and consultants. However, we cannot guarantee that
our trade  secrets,  unpatented  technology or  proprietary  knowledge  will not
become  known  or be  independently  developed  by  competitors.  If any of this
proprietary information becomes known to third parties, we may have no practical
recourse against these parties.

                                       9


      WE MAY NOT BE ABLE TO REALIZE THE DEFERRED TAX ASSET RELATING TO OUR
TAX NET OPERATING LOSS CARRY FORWARD.

      As of December  31,  2003,  IRIS has deferred tax assets in excess of $8.0
million resulting from the differences  between the financial  statement and the
tax bases of assets and  liabilities  using  enacted tax rates in effect for the
year in which the  differences  are  expected to reverse.  There is no assurance
that  we will  be  able  to  generate  taxable  income  in the  years  that  the
differences reverse.

      DEFECTIVE PRODUCTS MAY HAVE AN ADVERSE EFFECT ON OUR REPUTATION AND
SUBJECT US TO LIABILITY.

      Our  products are used to gather  information  for medical  decisions  and
diagnosis.  Accordingly,  a defect in the design or manufacture of our products,
or a failure of our products to perform for the use that we specify,  could have
a material  adverse  effect on our  reputation in the industry and subject us to
claims of  liability  arising  from  inaccurate  or  allegedly  inaccurate  test
results.  Misuse of our products by a technician  that results in  inaccurate or
allegedly  inaccurate  test  results  could  similarly  subject  us to claims of
liability.  We currently maintain product liability insurance coverage for up to
$1.0 million per  incident  and up to an aggregate of $2.0 million per year.  We
also  currently  maintain a product  liability  umbrella  policy for coverage of
claims aggregating to $10.0 million. Although management believes this liability
coverage  is  sufficient  protection  against  future  claims,  there  can be no
assurance of the  sufficiency of these policies.  Any  substantial  underinsured
loss would have a material adverse effect on our financial condition and results
of  operations.  Furthermore,  any  impairment  of our  reputation  could have a
material  adverse effect on our revenues and prospects for future  business.  We
have not received any indication  that our insurance  carrier will not renew our
product  liability  insurance at or near current  premiums,  however,  we cannot
guarantee  that this will continue to be the case.  In addition,  any failure to
comply with FDA regulations governing  manufacturing  practices could hamper our
ability to defend against product liability lawsuits.

      OUR BUSINESS COULD SUFFER IF WE ARE UNSUCCESSFUL IN INTEGRATING
BUSINESS COMBINATIONS, ADDITIONAL PRODUCT LINES OR STRATEGIC ALLIANCES.

      While we have no commitments  or agreements to acquire other  companies or
product lines or enter into strategic  alliances,  we may pursue acquisitions of
companies,  additional  product  lines or enter into  strategic  alliances.  Our
ability to grow through  acquisitions  or strategic  alliances  depends upon our
ability to identify,  negotiate, complete and integrate suitable acquisitions or
strategic alliance with our current  operations.  There can be no assurance that
we will be able to identify and enter into  acquisitions or strategic  alliances
on acceptable  terms. Even if we do so, we may experience any one or more of the
following:  difficulties  in integrating any acquired  companies,  personnel and
product  lines into our existing  business,  delays in realizing the benefits of
any acquired companies,  product lines or strategic alliances,  diversion of our
management's time and attention from other business  concerns,  a higher cost of
integration  than we expected,  assumption of undisclosed  liabilities,  adverse
market  reaction,  difficulties  in retaining key employees who are necessary to
manage these  acquisitions  or alliances and  additional  risks we may assume in
connection with such transactions.

RISKS RELATED TO OWNERSHIP OF OUR COMMON STOCK

      OUR CERTIFICATE OF INCORPORATION AND BYLAWS COULD DELAY OR PREVENT AN
ACQUISITION OR SALE OF OUR COMPANY.

      Our  Certificate  of  Incorporation  empowers  the Board of  Directors  to
establish  and issue a class of preferred  stock,  and to determine  the rights,
preferences  and  privileges  of  the  preferred   stock.   Our  Certificate  of
Incorporation  also  prohibits  stockholder  action by  written  consent.  These
provisions give the Board of Directors the ability to deter,  discourage or make
more  difficult  a change in  control of our  Company,  even if such a change in

                                       10


control would be in the interest of a significant  number of our stockholders or
if such a change in control  would provide our  stockholders  with a substantial
premium for their  shares over the  then-prevailing  market price for the common
stock.

      ANTI-TAKEOVER PROVISIONS OF DELAWARE LAW COULD DELAY OR PREVENT AN
ACQUISITION OF OUR COMPANY.

      We are  subject to the  anti-takeover  provisions  of  Section  203 of the
Delaware General Corporation Law, which regulates corporate acquisitions.  These
provisions could discourage potential  acquisition  proposals and could delay or
prevent a change in  control  transaction.  They  could  also have the effect of
discouraging others from making tender offers for our common stock or preventing
changes in our management.























                                       11


                                 USE OF PROCEEDS

      All proceeds  from the sale of the shares of common stock  offered by this
prospectus  will be for the  account of the  selling  stockholders.  We will not
receive any of the proceeds from the sale of the shares of our common stock.  If
and when all of the  warrants are  exercised,  we will,  however,  receive up to
$2,492,100,  which will be applied to working capital, reduction of indebtedness
or other general corporate purposes.

                              SELLING STOCKHOLDERS

      On April 22, 2004, we issued 2,130,000 shares of common stock and warrants
to purchase up to an additional  390,000 shares of common stock with an exercise
price of $7.80 per share in a private placement  transaction.  Net proceeds from
the private  placement  after  estimated  costs and expenses were  approximately
$11.6  million.  The private  placement was managed by Oppenheimer & Co. Inc. As
partial consideration for its services, Oppenheimer & Co. Inc. received warrants
to purchase up to 122,475 shares of common stock with an exercise price of $7.80
per  share.  The  warrants  issued  in the  private  placement  are  exercisable
immediately through and including the date occurring five years from the date of
their  issuance.  The warrants  issued to Oppenheimer & Co. Inc. are exercisable
beginning  on October 22, 2004 through and  including  the date  occurring  five
years from the date of their issuance.

     The following table shows the names of the selling stockholders,  and lists
the number of shares of our  common  stock  registered  for sale by each of them
under this prospectus.  It also shows the total number of shares of common stock
owned by them before and after the  offering,  and the  percentage  of our total
outstanding shares represented by these amounts.  We do not know when or in what
amounts a selling  stockholder  may choose to sell any of the shares  offered by
this prospectus. Because the selling stockholders may offer all or some of their
shares of common stock pursuant to this offering,  we cannot estimate the number
of  shares  of common  stock  that the  selling  stockholders  will  hold  after
completion of this  offering.  The table  assumes that each selling  stockholder
will sell all of the common  stock being  offered by this  prospectus  for their
account.  None of the selling stockholders has had a material  relationship with
us  within  the  past  three  years  other  than  as a  result  of  the  selling
stockholder's  ownership of our  securities,  except for Oppenheimer & Co. Inc.,
who acted as our  Placement  Agent for the  shares of common  stock that are the
subject of this prospectus.

     The following  table is based on information  provided to us by the selling
stockholders  named in the table, and does not necessarily  indicate  beneficial
ownership for any other purpose.  The selling  stockholders may,  however,  have
sold,  transferred or otherwise  disposed of all or a portion of their shares of
common stock since the date on which they provided such information.  The number
of shares of common  stock  beneficially  owned by the selling  stockholders  is
determined  in  accordance  with the  rules of the SEC.  The  number  of  shares
beneficially  owned  includes any shares as to which a person has sole or shared
voting power or investment power. Shares which a person has the right to acquire
within 60 days of the date of this  prospectus  are included in the shares owned
by that person and are treated as outstanding  for purposes of  calculating  the
ownership  percentage  of that person,  but not for any other  person.  The term
"selling   stockholders"  includes  the  stockholders  listed  below  and  their
transferees,  assignees,  pledgees,  donees or other successors.  The percent of
beneficial  ownership for each selling stockholder is based on 14,815,342 shares
of stock outstanding as of May 5, 2004.

                                       12



                                                       Percent of
                                                      Outstanding
                                      Number of        Shares of        Number of           Number of        Percent of
                                      Shares  of         Common         Shares of           Shares of        Shares of
                                     Common Stock         Stock        Common Stock        Common Stock      Common Stock
                                     Beneficiallly     Beneficially    to be Offered       Beneficially      Beneficially
                                     Owned Prior to    Owned Prior    Pursuant to this      Owned After      Owned After
Name of Selling Stockholder           Offering(1)      to Offering      Prospectus(2)     the Offering(3)   the Offering(3)
---------------------------------------------------------------------------------------------------------------------------
                                                                                                 

The Pinnacle Fund, LP                 1,493,000(4)      9.99%           1,150,000(5)          370,000           *

Sherleigh Associates, Inc. Defined
   Benefit Pension Plan                 689,600         4.65%           477,250               212,350           1.43%
Dolphin Offshore Partners               571,500         3.86%           471,500               100,000           *
Westpark Capital, LP                    260,500         1.76%            80,500               180,000           1.21%
SDS Capital Group SPC, Ltd.              92,000         *                92,000                     0           *
Incline Capital, LP                      73,000         *                23,000                50,000           *
WS Opportunity Fund International,
   Ltd.(6)                               69,200         *                57,500                11,700           *
WS Opportunity Fund (QP), LP(6)          64,720         *                53,820                10,900           *
WS Opportunity Fund, LP(6)               52,930         *                43,930                 9,000           *
Oppenheimer & Co. Inc.(7)                     0         *               122,475                     0           *
------------

* Represents less than One Percent of the outstanding shares.

(1)  Includes  shares  issuable  upon the exercise of  outstanding  warrants as
     follows:

        The Pinnacle Fund, LP                                           150,000
        Sherleigh Associates, Inc. Defined Benefit Pension  Plan         62,250
        Dolphin Offshore Partners                                        61,500
        SDS Capital Group SPC, Ltd.                                      12,000
        Westpark Capital, LP                                             10,500
        WS Opportunity Fund International, Ltd.                           7,500
        WS Opportunity Fund (QP), LP                                      7,020
        WS Opportunity Fund, LP                                           5,730
        Incline Capital, LP                                               3,000


(2)  Includes  the  shares  of  common  stock  which  are the  subject  of this
     Prospectus.

(3)  Assumes that all shares being  offered by each selling  stockholder  under
     this  prospectus  are  sold,  that  the  selling  stockholder  acquires  no
     additional  shares of common stock before the  completion of this offering,
     and that the  selling  stockholder  disposes  of no shares of common  stock
     other than those offered under this prospectus.

(4)  Includes  123,000  shares  issuable  upon the  exercise of an  outstanding
     warrant  granted  to  The  Pinnacle  Fund,  LP  in  the  private  placement
     transaction  on April 22,  2004.  We have only  included  a portion  of the
     150,000 shares covered by the warrant because, pursuant to the terms of the
     warrant,  the maximum number of shares that may be acquired by The Pinnacle
     Fund,  LP upon  any  exercise  of the  warrant  is  limited  to the  extent
     necessary  to insure that,  following  such  exercise,  the total number of
     shares of common stock then beneficially owned by The Pinnacle Fund, LP and
     its affiliates and any other persons whose  beneficial  ownership of common
     stock  would be  aggregated  with The  Pinnacle  Fund,  LP for  purposes of
     Section  13(d) of the  Exchange  Act,  does not exceed  9.999% of the total
     number of issued and outstanding shares of common stock (including for such

                                       13


     purpose the shares of common stock issuable upon such  exercise).  Based on
     14,815,342  shares of  common  stock  outstanding  as of May 5,  2004,  the
     maximum  number of  shares  issuable  to The  Pinnacle  Fund,  LP under the
     warrant are 123,000 shares.

(5)  Includes  150,000  shares   possibly  issuable  upon  the  exercise  of  an
     outstanding  warrant  granted  to The  Pinnacle  Fund,  LP in  the  private
     placement  transaction on April 22, 2004. Although,  as of May 5, 2004, the
     maximum  number of  shares  issuable  to The  Pinnacle  Fund,  LP under the
     warrant are 123,000  shares,  it is possible that an increase in the number
     of the  Company's  outstanding  shares of  common  stock or the sale of the
     Company's  common  stock by The  Pinnacle  Fund,  LP may allow The Pinnacle
     Fund,  LP to exercise  the  warrant for the full amount of 150,000  shares.
     (see footnote 4 to this table)

(6)  Patrick P.  Walker,  Reid S.  Walker and G. Stacy Smith each manage the WS
     Opportunity Fund  International,  Ltd., WS Opportunity Fund (QP), LP and WS
     Opportunity Fund, LP. In addition,  at least two of such individuals manage
     Walker Smith  Capital,  L.P.,  Walker Smith Capital  (QP),  L.P. and Walker
     Smith  International  Fund, Ltd. Because these individuals may be deemed to
     have  voting or  dispositive  control  over the shares held by all of these
     entities,  they may be deemed the  beneficial  owners of any shares held by
     such entities.  Walker Smith Capital, L.P., Walker Smith Capital (QP), L.P.
     and Walker Smith International Fund, Ltd. each hold the following number of
     shares of common stock of the Company,  none of which are including in this
     offering:

        Walker Smith Capital, L.P.                              5,300
        Walker Smith Capital (QP), L.P.                        28,300
        Walker Smith International Fund, Ltd.                  34,800

     The aggregate  number of shares of common stock held by WS Opportunity Fund
     International, Ltd., WS Opportunity Fund (QP), LP, WS Opportunity Fund, LP,
     Walker Smith  Capital,  L.P.,  Walker Smith Capital (QP),  L.P., and Walker
     Smith International  Fund, Ltd. is 100,000 shares,  which does not equal an
     amount greater than 1% of the  outstanding  shares of the Company's  common
     stock after the offering.

(7)  Includes  122,475  shares of common  stock  issuable  upon the  exercise of
     warrants by Oppenheimer & Co. Inc. on or after October 22, 2004.




                                       14



                              PLAN OF DISTRIBUTION

      We are registering the shares on behalf of the selling  stockholders.  The
selling   stockholders  and  their  successors,   including  their  transferees,
assignees,  pledges,  donees or other  successors,  may  dispose  of the  shares
covered by this prospectus  from time to time for their own accounts.  They will
act  independently  of us in making decisions  regarding the timing,  manner and
size of each sale.  They may sell their shares on the Nasdaq  National Market or
other  exchanges,  in the  over-the-counter  market or in  privately  negotiated
transactions.  They may sell their  shares  directly  or  through  underwriters,
broker-dealers or agents, who may receive compensation in the form of discounts,
concessions, or commissions from the selling stockholders or from the purchasers
of the shares. The compensation  received by a particular  underwriter,  broker,
dealer or agent might exceed customary commissions.

      The  shares of common  stock  may be sold in one or more  transactions  at
fixed prices, at prevailing market prices at the time of sale, at prices related
to the  prevailing  market prices,  at varying prices  determined at the time of
sale, or at negotiated prices.

      The selling  stockholders  may dispose of their shares  through any of the
following methods or any combination of these methods:

        o  purchases  by a broker or dealer as a  principal  and  resale by that
           broker or dealer for its own account under this prospectus;

        o  ordinary brokerage  transactions and transactions in which the broker
           solicits purchasers, which may include long or short sales made after
           the  effectiveness  of  the  registration  statement  of  which  this
           prospectus is a part;

        o  cross trades or block trades in which the broker or dealer engaged to
           make the sale will attempt to sell the  securities  as an agent,  but
           may  position  and  resell a portion of the block as a  principal  to
           facilitate the transaction;

        o  through the writing of options;

        o  in other ways not  involving  market  makers or  established  trading
           markets,  including  direct sales to purchasers or sales made through
           agents;

        o  any combination of the above transactions; or

        o  any other lawful method.

      In addition,  any securities  covered by this prospectus which qualify for
sale in compliance with Rule 144  promulgated  under the Securities Act of 1933,
as amended, may be sold under Rule 144 rather than under this prospectus.

      The  selling   stockholders  may  enter  into  hedging  transactions  with
broker-dealers in connection with  distributions of the shares or otherwise.  In
these transactions,  broker-dealers may engage in short sales of common stock in
the course of hedging the positions they assume with the selling stockholders.

      The selling  stockholders  also may sell shares  short and  redeliver  the
shares to close out such short  positions.  The selling  stockholders  may enter
into options or other transactions with broker-dealers that require the delivery
to the  broker-dealer  of the  shares.  The  broker-dealer  may then  resell  or
otherwise  transfer the shares covered by this prospectus  (which may be amended

                                       15


or supplemented to reflect the transaction).  The selling  stockholders also may
loan or pledge the shares to a broker-dealer or another  financial  institution.
If a selling  stockholder  defaults on the loan or the obligation secured by the
pledge,  the  broker-dealer  or  institution  may sell the  shares  so loaned or
pledged under this  prospectus  (which may be amended or supplemented to reflect
the transaction).

      Broker-dealers  or  agents  may  receive   compensation  in  the  form  of
commissions,   discounts   or   concessions   from  the  selling   stockholders.
Broker-dealers  or agents  may also  receive  compensation  from the  purchasers
shares for whom they act as agents or to whom they sell as principals,  or both.
Compensation  received  by a  particular  broker-dealer  might be in  excess  of
customary commissions and will be in amounts to be negotiated in connection with
the sale.

      Broker-dealers or agents and any other participating broker-dealers or the
selling  stockholders may be deemed to be  "underwriters"  within the meaning of
Section  2(11)  of the  Securities  Act in  connection  with  sales  of  shares.
Accordingly,  any such commission,  discount or concession  received by them and
any  profit on the resale of the  shares  purchased  by them may be deemed to be
underwriting discounts or commissions under the Securities Act.

      The selling  stockholders  have advised us that they have not entered into
any  agreements,   understandings  or  arrangements  with  any  underwriters  or
broker-dealers  regarding  the  sale  of  their  shares  and  that  there  is no
underwriter or  coordinating  broker acting in connection with the proposed sale
of shares by the selling stockholders.

      We have agreed to maintain the effectiveness of the registration statement
of which this prospectus is a part until the earliest to occur of the following:

        o   the date on which all shares held by the selling stockholders can be
            sold immediately  without  registration and free of volume or manner
            of sale restrictions pursuant to Rule 144; or

        o   the date on which all shares  offered by this  prospectus  have been
            sold or otherwise  transferred by the selling stockholders  pursuant
            to and in accordance with the  registration  statement,  or in other
            transactions   that  would   result  in  the   removal  of  transfer
            restrictions and restrictive legends from the shares.

We may suspend  the selling  stockholders'  rights to resell  shares  under this
prospectus  for limited  periods if required  to do so by  regulatory  action or
because material information or events affecting us are not adequately disclosed
in the then available prospectus.

      We have agreed to pay the  expenses of  registering  the shares  under the
Securities  Act,  including  registration  and filing fees,  printing  expenses,
administrative  expenses  and certain  legal and  accounting  fees.  The selling
stockholders  will bear all discounts,  commissions or other amounts  payable to
underwriters,  dealers  or  agents as well as fees and  disbursements  for legal
counsel  retained by any selling  stockholder.  We have also agreed to indemnify
the  selling  stockholders   against  certain  liabilities,   including  certain
liabilities under the Securities Act.

      The  selling  stockholders  may agree to  indemnify  any agent,  dealer or
broker-dealer  that  participates  in  transactions  involving  sales of  shares
against liabilities, including liabilities arising under the Securities Act.

      Because the selling stockholders may be deemed to be "underwriters" within
the meaning of Section  2(11) of the  Securities  Act, the selling  stockholders
will be subject to the prospectus  delivery  requirements of the Securities Act.

                                       16


If we are required to supplement this prospectus or  post-effectively  amend the
registration  statement  to  disclose a  specific  plan of  distribution  of the
selling stockholders,  the supplement or amendment will describe the particulars
of the plan of  distribution,  including  the shares of common  stock,  purchase
price and names of any agent,  broker,  dealer,  or underwriter or  arrangements
relating to any such entity or applicable commissions.

      Under applicable rules and regulations  under the Securities  Exchange Act
of 1934, as amended,  no person  engaged in the  distribution  of the shares may
simultaneously  engage in market  making  activities  with respect to our common
stock for a restricted  period before the commencement of the  distribution.  In
addition,  the selling stockholders will be subject to applicable  provisions of
the Securities  Exchange Act of 1934, as amended,  and the associated  rules and
regulations  under the  Securities  Exchange Act of 1934, as amended,  including
Regulation  M, the  provisions  of which may limit the timing of  purchases  and
sales of the shares by the selling stockholders.

      We will  make  copies of this  prospectus  (as it may be  supplemented  or
amended  from  time to time)  available  to the  selling  stockholders  and have
informed  the  selling  stockholders  of the  need  to  deliver  copies  of this
prospectus to purchasers at or before the time of any sale of the shares.

      Our common stock is traded on the Nasdaq  National Market under the symbol
"IRIS." The transfer agent for our shares of common stock is  Continental  Stock
Transfer & Trust  Company,  17 Battery Place,  New York,  New York,  10004-1123,
Attention: William F. Seegraber.

                                  LEGAL MATTERS

      The  validity  of the  issuance  of the  shares  of  common  stock in this
offering will be passed upon for us by Sheppard,  Mullin, Richter & Hampton LLP,
800 Anacapa Street, Santa Barbara, California 93101.

                                     EXPERTS

      The consolidated financial statements as of December 31, 2003 and 2002 and
for the three  years in the period  ended  December  31,  2003  incorporated  by
reference in this Prospectus have been audited by BDO Seidman,  LLP, independent
certified  public  accountants,  to the extent and for the  periods set forth in
their report  incorporated  herein by reference,  and are incorporated herein in
reliance  upon such report  given upon the  authority of said firm as experts in
auditing and accounting.

                       WHERE YOU CAN FIND MORE INFORMATION

      Because we are subject to the  informational  requirements  of the SEC, we
file reports,  proxy statements and other information with the SEC. You may read
and copy these reports,  proxy  statements  and other  information at the public
reference room maintained by the SEC at the following address:

                        Public Reference Room
                        450 Fifth Street, N.W.
                        Washington, D.C. 20549

      You may obtain  information on the operation of the public  reference room
by calling  the SEC at (800)  SEC-0330.  In  addition,  we are  required to file
electronic  versions  of those  materials  with the SEC  through the SEC's EDGAR
system.  The SEC  maintains  a web site at  http://www.sec.gov,  which  contains
reports,  proxy statements and other information regarding registrants that file
electronically with the SEC.

                                       17


      We have filed with the SEC a registration  statement on Form S-3 under the
Securities Act with respect to the securities offered with this prospectus. This
prospectus  does  not  contain  all  of  the  information  in  the  registration
statement,  parts of which we have  omitted,  as  allowed  under  the  rules and
regulations  of the SEC.  You should  refer to the  registration  statement  for
further information with respect to us and our securities.  Statements contained
in this  prospectus as to the contents of any contract or other document are not
necessarily  complete  and, in each  instance,  we refer you to the copy of each
contract or document filed as an exhibit to the registration  statement.  Copies
of the  registration  statement,  including  exhibits,  may be obtained  without
charge at the website  maintained by the SEC at www.sex.gov, or may be inspected
without charge at the SEC's  principal  office in Washington,  D.C., and you may
obtain copies from that office upon payment of the fees prescribed by the SEC.

      We will  furnish  without  charge  to each  person  to whom a copy of this
prospectus is delivered, upon written or oral request, a copy of the information
that has been  incorporated by reference into this prospectus  (except exhibits,
unless they are  specifically  incorporated by reference into this  prospectus).
You  should  direct  any  requests  for  copies  to:  Investor  Relations,  IRIS
International,  Inc.,  9172  Eton  Avenue,  Chatsworth,  California  91311-5874;
telephone number (818) 709-1244.

                      INFORMATION INCORPORATED BY REFERENCE

      The Securities and Exchange Commission,  or SEC, allows us to "incorporate
by reference" in this prospectus the information that we file with the SEC. This
means that we can disclose  important  information  by  referring  the reader to
those SEC filings. The information incorporated by reference is considered to be
part of this prospectus,  and later information we file with the SEC will update
and supersede this information. We incorporate by reference the documents listed
below and any future filings made with the SEC under Section 13(a),  13(c),  14,
or  15(d)  of the  Securities  Exchange  Act  prior  to the  termination  of the
offering:

        o  our Annual Report on Form 10-K for our fiscal year ended December 31,
           2003 and any amendments thereto;

        o  our Quarterly  Report on Form 10-Q for our fiscal quarter ended March
           30, 2004;

        o  our Current  Report on Form 8-K filed with the SEC April 26, 2004;

        o  the  description  of our common stock  contained in our  registration
           statement  on Form 8-A filed with the SEC on June 3, 1981,  including
           any  amendment  or report  filed for the  purpose  of  updating  this
           description.

     You may obtain copies of those  documents on the website  maintained by the
SEC at www.sec.gov, or from us, free of cost, by contacting us at the address or
telephone number provided in "Where You Can Find More  Information"  immediately
above.


                                       18


                                     PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

      The  following  table  sets  forth the costs and  expenses  payable by the
Registrant in  connection  with the sale of common stock being  registered.  All
amounts are estimates except the Securities and Exchange Commission registration
fee.

   Securities and Exchange Commission registration fee..............    2,056.01

   Nasdaq National Market additional listing fee....................   21,300.00

   Accounting fees and expenses......................................  15,000.00

   Legal fees and expenses...........................................  15,000.00

   Printing and related fees.........................................   5,000.00

   Miscellaneous.....................................................   5,000.00

   Total............................................................. $63,356.01
                                                                      ==========


ITEM 15.    INDEMNIFICATION OF DIRECTORS AND OFFICERS.

      Section  145 of the  Delaware  General  Corporation  Law  provides  that a
corporation may indemnify  directors and officers as well as other employees and
individuals against expenses,  including attorneys' fees,  judgments,  fines and
amounts paid in  settlement  in  connection  with  specified  actions,  suits or
proceedings,  whether civil,  criminal,  administrative or investigative  (other
than an action by or in the right of the corporation or a derivative action), if
they acted in good faith and in a manner  they  reasonably  believed to be in or
not opposed to the best  interests of the  corporation  and, with respect to any
criminal action or proceedings, had no reasonable cause to believe their conduct
was unlawful.

      A similar standard is applicable in the case of derivative actions, except
that  indemnification  only  extends to  expenses  (including  attorneys'  fees)
actually and reasonably incurred in connection with the defense or settlement of
such action,  and the statute  requires court  approval  before there can be any
indemnification  where the person seeking  indemnification has been found liable
to the  corporation.  The statute  provides  that it is not  exclusive  of other
indemnification   that  may  be  granted  by  a  corporation's   Certificate  of
Incorporation,  Bylaws, disinterested director vote, stockholder vote, agreement
or otherwise.

            As permitted by Section 145 of the Delaware General Corporation Law,
Article VIII of our Certificate of Incorporation, as amended, provides:



                                      II-1


            "The  corporation  shall to the fullest extent  permitted by Section
            145 of the Delaware  General  Corporation  Law indemnify all persons
            whom it may indemnify pursuant thereto."

      Our Bylaws  provide for  indemnification  of officers and directors to the
fullest extent  permitted by Delaware law. In addition,  the Registrant has, and
intends in the future to enter into,  agreements to provide  indemnification for
directors and officers in addition to that provided for in the Bylaws.

      We maintain insurance on behalf of any person who is a director or officer
against any loss arising from any claim asserted against any of them and expense
incurred by any of them in any capacity, subject to certain exclusions.

ITEM 16.    EXHIBITS.

   Exhibit
    Number                          Description of Exhibit
    ------                          ----------------------

     4.1(1)    Form of Investor Warrant to Purchase Common Stock

     4.2(1)    Placement Agent Warrant to Purchase Common Stock, dated April
               19, 2004

     5.1       Opinion of Sheppard, Mullin, Richter & Hampton, LLP, together
               with consent

    10.1(1)    Form of Common Stock Purchase Agreement

    23.1       Consent of Sheppard, Mullin, Richter & Hampton, LLP (included in
               its opinion filed as Exhibit 5.1)

    23.2       Consent of BDO Seidman, LLP, Independent Auditors

    24.1*      Power of Attorney

* Previously filed.


(1) Incorporated  by reference to the  Registrant's  Current  Report on Form 8-K
    filed with the Securities and Exchange Commission on April 26, 2004.

ITEM 17.    UNDERTAKINGS.

      (a) The undersigned registrant hereby undertakes:

          (1)  To file, during  any  period  in which  offers or sales are being
               made, a post-effective  amendment to this Registration Statement:

               (i)   To include any prospectus  required by Section  10(a)(3) of
                     the Securities Act;

                                      II-2


              (ii)   To reflect in the  prospectus  any facts or events  arising
                     after the effective date of this Registration Statement (or
                     the most recent  post-effective  amendment  thereof) which,
                     individually  or in the aggregate,  represent a fundamental
                     change in the  information  set forth in this  Registration
                     Statement.  Notwithstanding the foregoing,  any increase or
                     decrease  in volume  of  securities  offered  (if the total
                     dollar value of  securities  offered  would not exceed that
                     which was  registered)  and any  deviation  from the low or
                     high end of the  estimated  maximum  offering  range may be
                     reflected  in  the  form  of  prospectus   filed  with  the
                     Commission  pursuant to Rule  424(b) if, in the  aggregate,
                     the changes in volume and price represent no more than a 20
                     percent change in the maximum aggregate  offering price set
                     forth in the "Calculation of Registration Fee" table in the
                     effective registration statement; and

             (iii)   To include any  material  information  with  respect to the
                     plan  of  distribution  not  previously  disclosed  in this
                     Registration  Statement  or any  material  change  to  such
                     information in this Registration Statement;

PROVIDED,  HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
registration statement is on Form S-3, Form S-8 or Form S-3, and the information
required to be included in a  post-effective  amendment by those  paragraphs  is
contained in periodic  reports filed with or furnished to the  Commission by the
registrant  pursuant to Section 13 or 15(d) of the Securities  Exchange Act that
are incorporated by reference in this Registration Statement.

(2)   That,  for the purpose of determining  any liability  under the Securities
      Act,  each  such  post-effective  amendment  shall be  deemed  to be a new
      registration statement relating to the securities offered therein, and the
      offering of such securities at that time shall be deemed to be the initial
      bona fide offering thereof.

(3)   To remove from registration by means of a post-effective  amendment any of
      the securities  being registered which remain unsold at the termination of
      the offering.

(b)   The  undersigned  registrant  hereby  undertakes  that,  for purposes of
      determining  any liability  under the Securities Act, each filing of the
      registrant's  annual report  pursuant to  Section 13(a)  or 15(d) of the
      Exchange Act (and, where applicable,  each filing of an employee benefit
      plan's  annual  report  pursuant  to  Section 15(d)  of  the  Securities
      Exchange  Act) that is  incorporated  by reference in this  Registration
      Statement shall be deemed to be a new  registration  statement  relating
      to the securities  offered therein,  and the offering of such securities
      at that  time  shall be  deemed to be the  initial  bona  fide  offering
      thereof.

(c)   Insofar as indemnification  for liabilities arising under the Securities
      Act may be permitted to directors,  executive  officers and  controlling
      persons of the  registrant  pursuant  to the  foregoing  provisions,  or
      otherwise,  the  registrant  has been advised that in the opinion of the
      Commission  such  indemnification  is against public policy as expressed
      in the Securities  Act and is,  therefore,  unenforceable.  In the event
      that a claim for  indemnification  against such liabilities  (other than
      the  payment  by the  registrant  of  expenses  incurred  or  paid  by a
      director,  officer  or  controlling  person  of  the  registrant  in the
      successful  defense of any action,  suit or  proceeding)  is asserted by
      such  director,  officer or  controlling  person in connection  with the
      securities being registered,  the registrant will, unless in the opinion
      of its counsel  the matter has been  settled by  controlling  precedent,
      submit to a court of appropriate  jurisdiction the question whether such
      indemnification  by it is  against  public  policy as  expressed  in the
      Securities  Act and will be governed by the final  adjudication  of such
      issue.

                                      II-3



                                  SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for filing on Form S-3 and has duly caused this Amendment No. 1 to
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in the City of Chatsworth,  State of  California,  on May 21,
2004.

                                    INTERNATIONAL REMOTE IMAGING
                                    SYSTEMS, INC.


                                    By:  /s/ Cesar M. Garcia
                                         _______________________________________
                                         Cesar M. Garcia,
                                         Chief Executive Officer


                                    By: /s/ Martin G. Paravato
                                        _______________________________________
                                         Martin G. Paravato,
                                         Chief Financial Officer





                                      II-4



     Pursuant to the requirements of the Securities Act, this Amendment No. 1 to
Registration  Statement  has been signed below by the  following  persons in the
capacities and on the dates indicated.


         Signature                        Title                        Date
         ---------                        -----                        ----

/s/ Cesar M. Garcia*              Chief Executive Officer           May 21, 2004
------------------------------    and Director
Cesar M. Garcia                   (Principal Executive Officer)


/s/ Martin G. Paravato            Chief Financial Officer           May 21, 2004
------------------------------    and Secretary
Martin G. Paravato                (Principal Financial and
                                  Accounting Officer)

/s/ Richard H. Williams*          Director                          May 21, 2004
------------------------------
Richard H. Williams


/s/ Steven M. Besbeck*            Director                          May 21, 2004
------------------------------
Steven M. Besbeck


/s/ Thomas F. Kelley*             Director                          May 21, 2004
------------------------------
Thomas F. Kelley


/s/ Richard G. Nadeau*            Director                          May 21, 2004
------------------------------
Richard G. Nadeau


/s/ Michael D. Matte*             Director                          May 21, 2004
------------------------------
Michael D. Matte

*By:  /s/ Martin G. Paravato
      -------------------
      Martin G. Paravato
      Attorney-in-Fact
      Mary 21, 2004


                                      II-5



                                      INDEX

   Exhibit
    Number                          Description of Exhibit
   --------    -----------------------------------------------------------------

     4.1(1)    Form of Investor Warrant to Purchase Common Stock

     4.2(1)    Placement Agent Warrant to Purchase Common Stock, dated April
               19, 2004

     5.1       Opinion of Sheppard, Mullin,  Richter & Hampton, LLP, together
               with consent

    10.1(1)    Form of Common Stock Purchase Agreement

    23.1       Consent of Sheppard, Mullin,  Richter & Hampton, LLP (included
               in its opinion filed as Exhibit 5.1)

    23.2       Consent of BDO Seidman, LLP, Independent Auditors

    24.1*      Power of Attorney

* Previously filed.


(1) Incorporated  by reference  to the Registrant's  Current  Report on Form 8-K
    filed with the Securities and Exchange Commission on April 26, 2004.