AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON ______, 2005

                                                      REGISTRATION NO. 333-_____
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                 ---------------
                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                 ---------------

                           ACACIA RESEARCH CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

               DELAWARE                                     95-4405754
    (STATE OR OTHER JURISDICTION OF                      (I.R.S. EMPLOYER
    INCORPORATION OR ORGANIZATION)                    IDENTIFICATION NUMBER)

                            500 NEWPORT CENTER DRIVE
                         NEWPORT BEACH, CALIFORNIA 92660
                      (ADDRESS PRINCIPAL EXECUTIVE OFFICES)

                      2002 COMBIMATRIX STOCK INCENTIVE PLAN
                  2002 ACACIA TECHNOLOGIES STOCK INCENTIVE PLAN
                           (FULL TITLES OF THE PLANS)

                                  PAUL R. RYAN
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                            500 NEWPORT CENTER DRIVE
                         NEWPORT BEACH, CALIFORNIA 92660
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (949) 480-8300
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)

                                   COPIES TO:


                                                   CALCULATION OF REGISTRATION FEE
============================================== ==================== ===================== ==================== =====================
                                                                      PROPOSED MAXIMUM     PROPOSED MAXIMUM                         
         TITLE OF EACH CLASS OF                   AMOUNT TO BE       OFFERING PRICE PER   AGGREGATE OFFERING        AMOUNT OF       
       SECURITIES TO BE REGISTERED               REGISTERED (1)          SHARE (2)               PRICE           REGISTRATION FEE   
---------------------------------------------- -------------------- --------------------- -------------------- ---------------------
                                                                                                             
2002 CombiMatrix Stock Incentive Plan                                                                                               
Acacia Research - CombiMatrix Common                                                                                                
Stock, $0.001 par value                                                                                                             
(options available for future grant) .........     600,000 shares           $1.96              $1,176,000            $138.42
---------------------------------------------- -------------------- --------------------- -------------------- ---------------------
2002 Acacia Technologies Stock Incentive Plan                                                                                       
Acacia Research - Acacia Technologies                                                                                               
Common Stock, $0.001 par value                                                                                                      
(options available for future grant) .........     500,000 shares           $4.66              $2,330,000            $274.24
---------------------------------------------- -------------------- --------------------- -------------------- ---------------------
                                                                                                                                    
                                    TOTAL        1,100,000 shares                                                    $412.66
============================================== ==================== ===================== ==================== =====================

(1)   Represents additional shares issuable under the 2002 CombiMatrix Stock
      Incentive Plan and the 2002 Acacia Technologies Stock Incentive Plan
      (together, the "Plans") by reason of the automatic share increase
      provisions of each of the Plans. This Registration Statement shall also
      cover any additional shares of Common Stock attributable to these
      registered shares which become issuable under the Plans by reason of any
      stock dividend, stock split, recapitalization or other similar transaction
      effected without the Registrant's receipt of consideration which results
      in an increase in the number of the outstanding shares of the Registrant's
      Common Stock.

(2)   The proposed maximum offering price per share is estimated solely for the
      purpose of computing the amount of the registration fee under Rule 457(c)
      and (h). With respect to the 600,000 shares of Acacia Research -
      CombiMatrix Common Stock reserved for future issuance under the 2002
      CombiMatrix Stock Incentive Plan, the proposed maximum offering price per
      share is based on the average of the high and low sale price of $1.96 per
      share of the Acacia Research - CombiMatrix Common Stock reported on the
      Nasdaq National Market on August 12, 2005. With respect to the 500,000
      shares of Acacia Research - Acacia Technologies Common Stock reserved for
      future issuance under the 2002 Acacia Technologies Stock Incentive Plan,
      the proposed maximum offering price per share is based on the average of
      the high and low sale price of $$4.66 per share of the Acacia Research -
      Acacia Technologies Common Stock reported on the Nasdaq National Market on
      August 12, 2005.



         This Registration Statement on Form S-8 registers the offer and sale of
an additional 600,000 shares of Acacia Research-CombiMatrix Common Stock for
issuance under the 2002 CombiMatrix Stock Incentive Plan and an additional
500,000 shares of Acacia Research-Acacia Technologies Common Stock for issuance
under the 2002 Acacia Technologies Stock Incentive Plan. The contents of the
prior Registration Statement relating to the Plans, File No. 333-102181, are
incorporated herein by reference.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

         The Registrant hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Securities and
Exchange Commission (the "Commission"):

         (a)      The Registrant's Annual Report on Form 10-K for the fiscal
                  year ended December 31, 2004, as filed with the Commission on
                  March 15, 2005;

         (b)      The Registrant's Report on Form 8-K/A as filed with the
                  Commission on April 11, 2005;

         (c)      The Registrant's Report on Form 8-K as filed with the
                  Commission on April 27, 2005;

         (d)      The Registrant's Quarterly Report on Form 10-Q for the quarter
                  ended March 31, 2005, as filed with the Commission on May 6,
                  2005;

         (e)      The Registrant's Prospectus on Form 424(b)(4) as filed with
                  the Commission on May 10, 2005;

         (f)      The Registrant's Report on Form 8-K as filed with the
                  Commission on June 30, 2005;

         (g)      The Registrant's Prospectus on Form 424(b)(5) as filed with
                  the Commission on June 30, 2005;

         (h)      The Registrant's Prospectus on Form 424(b)(5) as filed with
                  the Commission on July 1, 2005;

         (i)      The Registrant's Report on Form 8-K as filed with the
                  Commission on July 26, 2005;

         (j)      The Registrant's Quarterly Report on Form 10-Q for the quarter
                  ended June 30, 2005, as filed with the Commission on August 5,
                  2005;

         (k)      The description of the Registrant's Acacia
                  Research-CombiMatrix common stock and Acacia Research-Acacia
                  Technologies common stock contained in the Registration
                  Statement on Form 8-A as filed with the Commission on December
                  19, 2002 and any amendment or report filed with the Commission
                  for the purpose of updating such description.

         All reports and definitive proxy or information statements filed
pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of
1934 (the "1934 Act") after the date of this Registration Statement and prior to
the filing of a post-effective amendment which indicates that all securities
offered hereby have been sold or which deregisters all securities then remaining
unsold shall be deemed to be incorporated by reference into this Registration
Statement and to be a part hereof from the date of filing of such documents. Any
statement contained in a document incorporated or deemed to be incorporated by
reference herein shall be deemed to be modified or superseded for purposes of
this Registration Statement to the extent that a statement contained herein or
in any subsequently filed document which also is deemed to be incorporated by
reference herein modifies or supersedes such statement. Any such statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Registration Statement.



ITEM 6. 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-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.

         Acacia is contractually obligated to indemnify its officers pursuant to
separate indemnity agreements consistent with the foregoing standards of Section
145 of the DGCL, except that Acacia must reimburse any expenses incurred by its
officers within 30 days of request and must seek to recoup from its officers any
such expenses that are later determined to be unreasonable or not required to be
reimbursed under the terms of the agreement. Acacia has the burden of proving
that the expenses are unreasonable or that its officers are not entitled to
indemnification.

         As permitted by Section 145 of the Delaware General Corporation Law,
Article VII of Acacia's certificate of incorporation provides:

                  No person shall be personally liable to the Corporation or its
         stockholders for monetary damages for breach of fiduciary duty as a
         director, including without limitation for serving on a committee of
         the Board of Directors, except to the extent such exemption from
         liability or limitation thereof is not permitted under the DGCL as the
         same exists or hereafter may be amended. If the DGCL is amended after
         the date of the filing of this Certificate of Incorporation to
         authorize corporate action further eliminating or limiting the personal
         liability of directors, then the liability of a director of the
         Corporation shall be eliminated or limited to the fullest extent
         permitted by the DGCL as so amended. Any amendment, repeal or
         modification of this Article VII shall not adversely affect any right
         or protection of a director of the Corporation existing hereunder with
         respect to any act or omission occurring prior to such amendment,
         repeal or modification.

         Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers or persons controlling the
registrant pursuant to the foregoing provisions, Acacia has been informed that
in the opinion of the Securities and Exchange Commission such indemnification is
against public policy as expressed in the Act and is therefore unenforceable.

         Acacia has purchased insurance on behalf of any person who is or was a
director, officer, employee or agent of Acacia, or is or was serving at the
request of Acacia as a director, officer, employee or agent of another
corporation, partnership, joint venture, trust or other enterprise against any
liability asserted against him and incurred by him in any such capacity, or
arising out of his status as such, whether or not Acacia would have the power to
indemnify him against such liability under the provisions of Acacia's
certificate of incorporation.



ITEM 8.  EXHIBITS

  EXHIBIT
  NUMBER                                    EXHIBIT
------------      --------------------------------------------------------------

    5.1           Opinion of Greenberg Traurig LLP

   23.1           Consent of Independent Accountants regarding Acacia Research
                  Corporation

   23.2           Consent of Independent Accountants regarding Acacia
                  Technologies Group

   23.3           Consent of Independent Accountants regarding CombiMatrix Group

   23.4           Consent of Greenberg Traurig LLP (contained in Exhibit 5.1)

   24.1           Power of Attorney (contained on page II-2 of this registration
                  statement)

   99.1           2002 CombiMatrix Stock Incentive Plan*

   99.2           2002 Acacia Technologies Stock Incentive Plan*

------------------
* Incorporated by reference from Acacia Research's Registration Statement on 
  Form S-8 (File No. 333-102181).



                                   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-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Newport Beach, State of California, on the 16th day
of August, 2005.

                                       ACACIA RESEARCH CORPORATION

                                       By:  /s/ Paul R. Ryan                    
                                            ------------------------------------
                                            Paul R. Ryan
                                            CHAIRMAN AND CHIEF EXECUTIVE OFFICER


                                POWER OF ATTORNEY

         The undersigned directors and officers of Acacia Research Corporation
hereby constitute and appoint Paul R. Ryan and Clayton J. Haynes and each of
them, as his true and lawful attorneys-in-fact and agents, with full power to
act without the other and with full power of substitution and resubstitution,
for him and in his name, place and stead, in any and all capacities to sign any
and all amendments (including post-effective amendments) to this registration
statement, and new registration statements relating to this Form S-8, and to
file the same with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, and each of them, full power and authority to do
and perform each and every act and thing requisite and necessary to be done in
and about the premises, as fully to all intents and purposes as he might or
could do in person, hereby ratifying and confirming all that said
attorneys-in-fact and agents, or either of them, or their or his substitute or
substitutes, may lawfully do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated.


            SIGNATURE                                  TITLE                             DATE
            ---------                                  -----                             ----
                                                                                  
/s/ Paul R. Ryan                        Chief Executive Officer and Chairman        August 16, 2005   
---------------------------------       (Principal Executive Officer)
Paul R. Ryan
                                                                                                      
/s/ Clayton J. Haynes                   Chief Financial Officer (Principal          August 16, 2005   
---------------------------------       Financial and Accounting Officer)
Clayton J. Haynes

/s/ Robert L. Harris, II                President and Director                      August 16, 2005   
---------------------------------                                                                     
Robert L. Harris, II                                                                                  

/s/ Thomas B. Akin                      Director                                    August 16, 2005   
---------------------------------                                                                     
Thomas B. Akin                                                                                        

                                        Director                                    
---------------------------------                                                                     
Rigdon Currie                                                                                         

/s/ Fred A. de Boom                     Director                                    August 16, 2005   
---------------------------------                                                                     
Fred A. de Boom                                                                                       
                                                                                                      
/s/ Edward W. Frykman                   Director                                    August 16, 2005   
---------------------------------                                                                     
Edward W. Frykman                                                                                     
                                                                                                      
/s/ G. Louis Graziadio, III             Director                                                      
---------------------------------                                                                     
G. Louis Graziadio, III                                                             August 16, 2005   
                                                                                                      
/s/ Amit Kumar                          Director                                                      
---------------------------------                                                                     
Amit Kumar                                                                          August 16, 2005   




                                  EXHIBIT INDEX

  EXHIBIT
  NUMBER                                    EXHIBIT
------------      --------------------------------------------------------------

    5.1           Opinion of Greenberg Traurig LLP

   23.1           Consent of Independent Accountants regarding Acacia Research
                  Corporation

   23.2           Consent of Independent Accountants regarding Acacia
                  Technologies Group

   23.3           Consent of Independent Accountants regarding CombiMatrix Group

   23.4           Consent of Greenberg Traurig LLP (contained in Exhibit 5.1)

   24.1           Power of Attorney (contained on page II-2 of this registration
                  statement)

   99.1           2002 CombiMatrix Stock Incentive Plan*

   99.2           2002 Acacia Technologies Stock Incentive Plan*

------------------
* Incorporated by reference from Acacia Research's Registration Statement on 
  Form S-8 (File No. 333-102181).