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


                                    FORM 8-K

                                 CURRENT REPORT
     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934


        Date of Report (Date of earliest event reported): March 28, 2006




                        Pioneer Natural Resources Company
             ------------------------------------------------------
             (Exact name of Registrant as specified in its charter)



          Delaware                    1-13245                75-2702753
----------------------------        ------------        -------------------
(State or other jurisdiction        (Commission          (I.R.S. Employer
     of incorporation)              File Number)        Identification No.)



5205 N. O'Connor Blvd., Suite 900, Irving, Texas               75039
------------------------------------------------            ----------
   (Address of principal executive offices)                 (Zip Code)


                                 (972) 444-9001
              ----------------------------------------------------
              (Registrant's telephone number, including area code)



                                 Not applicable
          -------------------------------------------------------------
          (Former name or former address, if changed since last report)


Check  the  appropriate  box  below  if the  Form  8-K  filing  is  intended  to
simultaneously  satisfy the filing obligation of the registrant under any of the
following provisions:

| | Written communications pursuant to Rule 425 under the Securities Act (17 CFR
    230.425)
| | Soliciting material  pursuant to Rule  14a-12 under the Exchange Act (17 CFR
    240.14a-12)
| | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange
    Act (17 CFR 240.14d-2(b))
| | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange
    Act (17 CFR 240.13e-4(c))








                        PIONEER NATURAL RESOURCES COMPANY

                                TABLE OF CONTENTS


                                                                         Page

Item 2.01.  Completion of Acquisition or Disposition of Assets.........    3

Item 9.01.  Financial Statements and Exhibits..........................    3

            (b)   Pro Forma Financial Information
            (d)   Exhibits.............................................    3

Signature..............................................................   13

Exhibit Index..........................................................   14




                                        2




                        PIONEER NATURAL RESOURCES COMPANY



Item 2.01.    Completion of Acquisition or Disposition of Assets

     On March 29, 2006, Pioneer Natural Resources Company (the "Company") issued
a news release that is attached hereto as exhibit 99.1. In the news release, the
Company  announced that its wholly-owned  subsidiary,  Pioneer Natural Resources
USA,  Inc.,  had closed the sale of certain  deepwater  Gulf of Mexico assets to
Marubeni Offshore Production (USA) Inc.  ("Marubeni"),  a subsidiary of Marubeni
Corporation, for cash proceeds of $1.3 billion before normal closing adjustments
which are currently estimated to be approximately $140 million.  Pioneer expects
to record an  after-tax  gain  associated  with the sale of  approximately  $425
million to $475 million. The sale of the assets was completed on March 28, 2006.

     See Item 9.01(b) for pro forma financial  information regarding the sale of
the  aforementioned  deepwater  Gulf of Mexico  assets  together  with pro forma
financial  information of the probable  completion of the  previously  announced
Stock Purchase Agreements and related agreements with Apache Corporation and its
subsidiaries  (collectively,  "Apache"), as a result of which Apache is expected
to purchase the Company's  Argentine  operations and assets for cash proceeds of
approximately $675 million, subject to normal closing adjustments.

Item 9.01. Financial Statements and Exhibits

     (b) Pro Forma Financial Information

         The  unaudited  pro  forma  financial  statements  of the  Company  are
         presented on pages 4 through 12.

     (d) Exhibits

         2.1   Purchase and Sale Agreement  by and between Pioneer as Seller and
               Marubeni as Purchaser  (incorporated by reference to  Exhibit 2.1
               to the Company's  Current Report on  Form 8-K,  File No. 1-13245,
               filed with the Securities and Exchange Commission on February 28,
               2006).

        99.1   News Release dated March 28, 2006.



                                       3






                        PIONEER NATURAL RESOURCES COMPANY

                    UNAUDITED PRO FORMA FINANCIAL STATEMENTS


     On February 22, 2006,  Pioneer Natural Resources USA, Inc. ("Pioneer USA"),
a wholly-owned subsidiary of Pioneer Natural Resources Company (the "Company" or
"Pioneer"),  entered into a Purchase and Sale  Agreement  through which Marubeni
Offshore   Production  (USA)  Inc.   ("Marubeni"),   a  subsidiary  of  Marubeni
Corporation,  would acquire certain deepwater Gulf of Mexico assets from Pioneer
USA for $1.3 billion, subject to normal closing adjustments.  The effective date
of the agreement is January 1, 2006,  and the purchase  price will be reduced by
the amount of the interim  period cash flow that Pioneer USA  received  from the
assets  between  the  effective  date of the  transaction  and closing and other
normal  adjustments  which are estimated to be approximately  $140 million.  The
closing of the transaction occurred on March 28, 2006.

     On January 16, 2006,  Pioneer  entered into Stock  Purchase  Agreements and
related  agreements  with  Apache  Corporation  ("Apache"),  by which  Apache is
expected to purchase Pioneer's Argentine operations and assets for cash proceeds
of  approximately  $675  million,  subject to normal  closing  adjustments.  The
transaction is expected to close in April 2006.

     The  accompanying  unaudited  pro  forma  financial  statements  have  been
prepared  to assist in analyses of the  financial  effects of the  divestitures.
This information is based on the historical  financial statements of the Company
and should be read in  conjunction  with the Company's  historical  consolidated
financial  statements and related notes included in the Company's 2005 Form 10-K
filed with the United States Securities and Exchange  Commission on February 17,
2006.

     The  accompanying  unaudited  pro forma  balance sheet of the Company as of
December  31, 2005 has been  prepared to give effect to the  divestitures  as if
they had each  occurred on December 31, 2005.  The  accompanying  unaudited  pro
forma  statement of  operations  of the Company for the year ended  December 31,
2005 has been  prepared to give effect to the  divestitures  as if they had each
occurred on January 1, 2005.

     The  unaudited  pro forma  financial  statements  included  herein  are not
necessarily  indicative  of  the  results  that  might  have  occurred  had  the
divestitures taken place on December 31, 2005 as it relates to the balance sheet
or  January 1, 2005 as it relates to the  statement  of  operations  and are not
intended to be a projection of future results.  In addition,  future results may
vary significantly from the results reflected in the accompanying  unaudited pro
forma financial  statements  because of normal production  declines,  changes in
commodity prices,  future acquisitions and divestitures,  future development and
exploration activities and other factors.




                                        4





                        PIONEER NATURAL RESOURCES COMPANY

                        UNAUDITED PRO FORMA BALANCE SHEET
                                December 31, 2005
                                 (in thousands)



                                                                       Pro Forma
                                                         --------------------------------------
                                                                      Deepwater        Other        Pro Forma
                                             Pioneer     Argentina    Properties    Adjustments      Pioneer
                                           -----------   ----------   ----------   -------------   -----------
ASSETS
                                                                                    
Current assets:
  Cash and cash equivalents..............  $    18,802   $   (2,516)   $      -    1,074,955 (a)   $   915,899
                                                                                    (175,342)(b)
  Accounts receivable:
    Trade, net...........................      336,062      (21,502)          -                        314,560
    Due from affiliates..................        1,596        4,324           -                          5,920
  Inventories............................       79,659      (12,013)          -                         67,646
  Prepaid expenses.......................       18,091       (1,113)          -                         16,978
  Deferred income taxes..................      158,878       (2,240)          -                        156,638
  Other current assets:
    Derivatives..........................        1,246           -            -                          1,246
    Other, net...........................        9,470          (34)          -                          9,436
                                            ----------    ---------     ---------                   ----------
     Total current assets................      623,804      (35,094)          -                      1,488,323
                                            ----------    ---------     ---------                   ----------
Property, plant and equipment, at cost:
  Oil and gas properties:
    Proved properties....................    8,499,253     (988,722)    (873,199)                    6,637,332
    Unproved properties..................      313,881      (95,331)     (34,811)                      183,739
  Accumulated depletion, depreciation
     and amortization....................   (2,577,946)     412,127      608,651                    (1,557,168)
                                            ----------    ---------     --------                    ----------
     Total property, plant and equipment.    6,235,188     (671,926)    (299,359)                    5,263,903
                                            ----------    ---------     --------                    ----------
Goodwill.................................      311,651           -            -                        311,651
Other property and equipment, net........       90,010       (2,249)          -                         87,761
Other assets:
  Derivatives............................        1,048           -            -                          1,048
  Other, net.............................       67,533       (8,295)          -                         59,238
                                            ----------    ---------     --------                    ----------
                                           $ 7,329,234   $ (717,564)   $(299,359)                  $ 7,211,924
                                            ==========    =========     ========                    ==========



       See accompanying notes to unaudited pro forma financial statements.


                                        5





                        PIONEER NATURAL RESOURCES COMPANY

                        UNAUDITED PRO FORMA BALANCE SHEET
                                December 31, 2005
                                 (in thousands)


                                                                       Pro Forma
                                                         --------------------------------------
                                                                      Deepwater        Other        Pro Forma
                                             Pioneer     Argentina    Properties    Adjustments      Pioneer
                                           -----------   ----------   ----------   -------------   -----------

LIABILITIES AND STOCKHOLDERS' EQUITY
                                                                                    
Current liabilities:
  Accounts payable:
    Trade................................  $   330,151   $  (26,024)   $      -                    $   304,127
    Due to affiliates....................       15,053         (881)          -                         14,172
  Interest payable.......................       40,314       (2,818)          -       (1,652)(c)        35,844
  Income taxes payable...................       22,470       (6,087)          -      196,094 (d)       212,477
  Other current liabilities:
    Derivatives..........................      320,098           -            -      (80,059)(b)       240,039
    Deferred revenue.....................      190,327           -            -                        190,327
    Other................................      114,942       (4,716)     (12,597)                       97,629
                                            ----------    ----------    --------                    ----------
      Total current liabilities..........    1,033,355      (40,526)     (12,597)                    1,094,615
                                            ----------    ----------    --------                    ----------

Long-term debt...........................    2,058,412           -            -     (900,000)(a)     1,158,412
Derivatives..............................      431,543           -            -      (95,283)(b)       336,260
Deferred income taxes....................      767,329      (14,596)          -          603 (c)       948,912
                                                                                     195,576 (d)
Deferred revenue.........................      664,511           -            -                        664,511
Other liabilities and minority interests.      156,982      (18,378)     (18,095)                      120,509
Stockholders' equity:
  Common stock...........................        1,470           -            -                          1,470
  Additional paid-in capital.............    3,775,794           -            -                      3,775,794
  Treasury stock, at cost................     (882,382)          -            -                       (882,382)
  Deferred compensation..................      (45,827)       3,736           -                        (42,091)
  Retained earnings (accumulated
    deficit).............................     (184,320)    (641,412)    (400,496)  1,974,955 (a)       358,106
                                                                                       1,049 (c)
                                                                                    (391,670)(d)
   Accumulated other comprehensive
    income (loss):
     Net deferred hedge losses,
       net of tax........................     (506,636)         -        131,829                      (374,807)
     Cumulative translation adjustment...       59,003       (6,388)         -                          52,615
                                            ----------    ---------     --------                    ----------
       Total stockholders' equity........    2,217,102     (644,064)    (268,667)                    2,888,705
                                            ----------    ---------     --------                    ----------
Commitments and contingencies
                                           $ 7,329,234   $ (717,564)   $(299,359)                  $ 7,211,924
                                            ==========    =========     ========                    ==========




       See accompanying notes to unaudited pro forma financial statements.


                                        6





                        PIONEER NATURAL RESOURCES COMPANY

                   UNAUDITED PRO FORMA STATEMENT OF OPERATIONS
                      For the year ended December 31, 2005
                      (in thousands, except per share data)



                                                                       Pro Forma
                                                         --------------------------------------
                                                                      Deepwater        Other        Pro Forma
                                             Pioneer     Argentina    Properties    Adjustments      Pioneer
                                           -----------   ----------   ----------   -------------   -----------
                                                                                    
Revenues:
  Oil and gas............................  $ 2,215,677   $ (172,187)  $ (593,077)                  $ 1,450,413
  Interest and other.....................       97,050       (6,039)     (59,437)                       31,574
  Gain on disposition of assets, net.....       60,496         (669)         -                          59,827
                                            ----------    ---------    ---------                    ----------
                                             2,373,223     (178,895)    (652,514)                    1,541,814
                                            ----------    ---------    ---------                    ----------
Costs and expenses:
  Oil and gas production.................      449,320      (38,756)     (64,125)                      346,439
  Depletion, depreciation and
    amortization.........................      568,018      (85,800)    (182,275)                      299,943
  Impairment of long-lived assets........          644           -            -                            644
  Exploration and abandonments...........      266,751      (24,527)     (39,087)                      203,137
  General and administrative.............      124,556       (9,030)         -                         115,526
  Accretion of discount on asset
    retirement obligations...............        7,876         (444)      (2,121)                        5,311
  Interest...............................      127,787       (1,700)         -       (23,097) (e)      102,990
  Other..................................      112,812       (3,910)      (8,212)                      100,690
                                            ----------    ---------    ---------                    ----------
                                             1,657,764     (164,167)    (295,820)                    1,174,680
                                            ----------    ---------    ---------                    ----------
Income from continuing operations before
  income taxes...........................      715,459      (14,728)    (356,694)                      367,134
Income tax provision.....................     (291,728)       6,863          -       138,623  (f)     (146,242)
                                            ----------    ---------    ---------                    ----------
Income from continuing operations .......  $   423,731   $   (7,865)  $ (356,694)                  $   220,892
                                            ==========    =========    =========                    ==========
Income per share from continuing
 operations:
  Basic..................................  $      3.09                                             $      1.61
                                            ==========                                              ==========
  Diluted................................  $      3.02                                             $      1.58
                                            ==========                                              ==========
Weighted average shares outstanding:
  Basic..................................      137,110                                                 137,110
                                            ==========                                              ==========
  Diluted................................      141,417                                                 141,417
                                            ==========                                              ==========




       See accompanying notes to unaudited pro forma financial statements.

                                        7





                        PIONEER NATURAL RESOURCES COMPANY

                NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS
                                December 31, 2005


Note 1.     Basis of Presentation

     The  accompanying  unaudited  pro forma  balance  sheet of Pioneer  Natural
Resources  Company (the "Company" or "Pioneer") as of December 31, 2005 has been
prepared to give effect to the  divestitures,  discussed  below,  as if they had
each occurred on December 31, 2005.

     The accompanying unaudited pro forma statement of operations of the Company
for the year ended  December  31,  2005 has been  prepared to give effect to the
divestitures,  discussed below, as if they had each occurred on January 1, 2005.
In  accordance  with  the  United  States  Securities  and  Exchange  Commission
presentation  rules,  the Company's  unaudited pro forma statement of operations
for the year ended December 31, 2005 does not include  income from  discontinued
operations,  net of tax,  recognized during 2005 of $110.8 million.  This amount
was  recorded  as a result of the  Company's  disposition  of the Martin  Creek,
Conroy Black and Lookout  Butte areas in Canada and certain  assets on the shelf
of the Gulf of Mexico.

     On February 22, 2006,  Pioneer Natural Resources USA, Inc. ("Pioneer USA"),
a wholly-owned subsidiary of Pioneer, entered into a Purchase and Sale Agreement
through which Marubeni Offshore Production (USA) Inc. ("Marubeni"), a subsidiary
of Marubeni  Corporation,  would acquire certain deepwater Gulf of Mexico assets
from Pioneer USA for $1.3 billion,  subject to normal closing  adjustments.  The
effective  date of the agreement is January 1, 2006, and the purchase price will
be  reduced by the  amount of the  interim  period  cash flow that  Pioneer  USA
received  from the assets  between the  effective  date of the  transaction  and
closing and other normal adjustments. The closing of the transaction occurred on
March 28, 2006.

     On January 16, 2006, the Company entered into Stock Purchase Agreements and
related  agreements  with  Apache  Corporation  ("Apache"),  by which  Apache is
expected to purchase Pioneer's Argentine operations and assets for cash proceeds
of  approximately  $675  million,  subject to normal  closing  adjustments.  The
transaction is expected to close in April 2006.

     Following  are  descriptions  of the  individual  columns  included  in the
accompanying unaudited pro forma financial statements and notes to unaudited pro
forma financial statements:

             Pioneer - Represents the  historical consolidated  balance sheet of
      the Company  as of December  31,  2005  and  the  historical  consolidated
      statement of operations from  continuing operations of the Company for the
      year ended December 31, 2005.

             Argentina - Represents  the  historical  balance  sheet  (excluding
      certain retained assets and liabilities,  primarily working capital items)
      as of December 31, 2005 and the historical statement of operations for the
      year ended December 31, 2005 of the Company's  Argentine operations  being
      divested.

             Deepwater  Properties   -   Represents   the   historical   assets,
      liabilities and accumulated  other comprehensive loss  (net deferred hedge
      losses, net of tax)  as of December 31,  2005 and the historical  revenues
      and  expenses   (including  associated  business   interruption  insurance
      recoveries and associated net  hedge losses)  for the  year ended December
      31, 2005 of the Company's deepwater Gulf of Mexico assets being divested.



                                        8




                        PIONEER NATURAL RESOURCES COMPANY

                NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS
                                December 31, 2005


Note 2.     Pioneer Pro Forma Adjustments

     (a) To adjust  for the  proceeds  and  related  costs  associated  with the
divestitures.  The  Company  utilized a portion of the  proceeds  to pay off the
outstanding debt associated with the Company's line of credit.  The following is
a  table  of the  estimated  proceeds,  transaction  costs  and  application  of
proceeds:



                                                                                  Deepwater
                                                                     Argentina    Properties       Total
                                                                     ---------    ----------    -----------
                                                                                (in thousands)

                                                                                       
      Gross proceeds.............................................    $ 675,000    $1,300,000    $ 1,975,000
      Proceeds adjustments.......................................       12,917         5,788         18,705
      Less - transaction costs...................................      (13,600)       (5,150)       (18,750)
                                                                      --------     ---------     ----------

      Net proceeds...............................................    $ 674,317    $1,300,638      1,974,955
                                                                      ========     =========
      Repayment of Company's line of credit......................                                  (900,000)
                                                                                                 ----------

      Increase in cash and cash equivalents......................                               $ 1,074,955
                                                                                                 ==========


      The following is a summarization of the gains on the divestitures:


                                                                                  Deepwater
                                                                     Argentina    Properties       Total
                                                                     ---------    ----------    -----------
                                                                                (in thousands)

                                                                                       

      Net proceeds...............................................    $  674,317   $1,300,638    $ 1,974,955
      Net investment in divestitures, excluding cash.............      (638,896)    (400,496)    (1,039,392)
                                                                      ---------    ---------     ----------

      Gains on disposition of assets.............................    $   35,421   $  900,142    $   935,563
                                                                      =========    =========     ==========


     (b) To  utilize  the  proceeds  from  the  divestitures  to  repay  the net
derivative obligations associated with the Deepwater Properties.

     (c) To  adjust  accrued  interest  associated  with  having  no  borrowings
outstanding  on the line of credit during 2005 as a result of  dispositions  and
the related income tax effect.

     (d) To adjust the balance sheet for income tax effects  associated with the
divestitures.

     (e) To adjust interest expense associated with the Company's line of credit
as  the  proceeds  from  the  divestitures   resulted  in  no  borrowings  being
outstanding during 2005. The adjustment is comprised of:

          o    elimination  of the  2005  historical  interest recognized by the
               Company associated with the line of credit and
          o    recognition of  interest costs  associated  with  undrawn amounts
               under the Company's line of credit.

     (f) To adjust  income tax expense  utilizing a 36.5 percent  effective  tax
rate for:

          o    the historical statement of operations activities associated with
               the Deepwater Properties and
          o    the adjustment to interest expense, see (e) above.




                                        9




                        PIONEER NATURAL RESOURCES COMPANY

                NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS
                                December 31, 2005



Note 3.     Supplementary Pro Forma Information on Oil and Gas Producing
            Activities

     The following supplementary pro forma information for oil and gas producing
activities is presented pursuant to the disclosure  requirements of Statement of
Financial  Accounting Standards No. 69, "Disclosures About Oil and Gas Producing
Activities"  assuming that the divestment of the Argentine  assets and deepwater
Gulf of Mexico assets occurred on January 1, 2005.











                                        10




                        PIONEER NATURAL RESOURCES COMPANY

                NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS
                                December 31, 2005


Pro Forma Reserve Quantity Information

     The following table sets forth the changes in net reserve quantities of oil
and natural gas liquids ("NGL") combined in thousands of barrels ("MBbls"),  gas
in  millions of cubic feet  ("MMcf")  and total in  thousands  of barrels of oil
equivalents  ("MBOE")  associated  with proved reserves on a pro forma basis for
the year ended December 31, 2005:


                                                      Oil &
                                                      NGLs              Gas
                                                     (MBbls)           (MMcf)            MBOE
                                                   ----------        ----------       ----------
                                                                             
Total Proved Reserves:
UNITED STATES
   Balance at January 1, 2005..................       354,279         2,874,143          833,303
   Revisions of previous estimates.............        (5.225)         (176,919)         (34,712)
   Purchases of minerals-in-place..............        65,800            83,179           79,663
   New discoveries and extensions..............           225           103,616           17,494
   Production..................................       (14,851)         (114,888)         (33,999)
   Sales of mineral-in-place...................       (21,727)          (97,410)         (37,964)
                                                   ----------        ----------       ----------
   Balance at December 31, 2005................       378,499         2,671,721          823,785
                                                   ==========        ==========       ==========
CANADA
   Balance at January 1, 2005..................         4,095           119,869           24,073
   Revisions of previous estimates.............           434            15,887            3,082
   Purchases of minerals-in-place..............           -                 292               49
   New discoveries and extensions..............           652            55,130            9,840
   Production..................................          (311)          (15,665)          (2,922)
   Sales of mineral-in-place...................        (2,447)          (44,999)          (9,947)
                                                   ----------        ----------       ----------
   Balance at December 31, 2005................         2,423           130,514           24,175
                                                   ==========        ==========       ==========
AFRICA
   Balance at January 1, 2005..................         8,271               -              8,271
   Revisions of previous estimates.............           184               -                184
   New discoveries and extensions..............         2,043            60,395           12,109
   Production..................................        (3,674)              -             (3,674)
                                                   ----------        ----------       ----------
   Balance at December 31, 2005................         6,824            60,395           16,890
                                                   ==========        ==========       ==========
TOTAL
   Balance at January 1, 2005..................       366,645         2,944,012          865,647
   Revisions of previous estimates.............        (4,607)         (161,032)         (31,446)
   Purchases of minerals-in-place..............        65,800            83,471           79,712
   New discoveries and extensions..............         2,920           219,141           39,443
   Production..................................       (18,836)         (130,553)         (40,595)
   Sales of mineral-in-place...................       (24,176)         (142,409)         (47,911)
                                                   ----------        ----------       ----------
   Balance at December 31, 2005................       387,746         2,862,630          864,850
                                                   ==========        ==========       ==========
Proved Developed Reserves:
   United States...............................       220,018         1,950,330          545,073
   Canada......................................         3,849           107,547           21,773
   Africa......................................         8,271               -              8,271
                                                   ----------        ----------       ----------
      Balance at January 1, 2005...............       232,138         2,057,877          575,117
                                                   ==========        ==========       ==========

   United States...............................       204,190         1,802,889          504,671
   Canada......................................         2,202            99,025           18,706
   Africa......................................         5,477               -              5,477
                                                   ----------        ----------       ----------
      Balance at December 31, 2005.............       211,869         1,901,914          528,854
                                                   ==========        ==========       ==========


                                       11




                        PIONEER NATURAL RESOURCES COMPANY

                NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS
                                December 31, 2005


Pro Forma Standardized Measure of Discounted Future Net Cash Flows

     The  following  tables  set  forth the pro forma  standardized  measure  of
discounted  future net cash flows  ("SMOG")  relating to proved oil, NGL and gas
reserves of the Company as of December 31, 2005, as well as changes  therein for
the year then ended (in thousands):


                                                                         
    SMOG:
      UNITED STATES
      Oil and gas producing activities:
         Future cash inflows..........................................      $ 36,093,210
         Future production costs......................................       (10,751,619)
         Future development costs.....................................        (2,674,228)
         Future income tax expense....................................        (7,350,220)
                                                                             -----------
                                                                              15,317,143
      10% annual discount factor......................................        (9,827,320)
                                                                             -----------
      Standardized measure of discounted future cash flows............      $  5,489,823
                                                                             ===========
      CANADA
      Oil and gas producing activities:
         Future cash inflows..........................................      $  1,062,258
         Future production costs......................................          (404,891)
         Future development costs.....................................           (46,312)
         Future income tax expense....................................          (166,333)
                                                                             -----------
                                                                                 444,722
      10% annual discount factor......................................          (190,655)
                                                                             -----------
      Standardized measure of discounted future cash flows............      $    254,067
                                                                             ===========
      AFRICA
      Oil and gas producing activities:
         Future cash inflows..........................................      $    718,481
         Future production costs......................................           (66,151)
         Future development costs.....................................          (250,705)
         Future income tax expense....................................          (140,185)
                                                                             -----------
                                                                                 261,440
      10% annual discount factor......................................          (105,271)
                                                                             -----------
      Standardized measure of discounted future cash flows............      $    156,169
                                                                             ===========
      TOTAL
      Oil and gas producing activities:
         Future cash inflows..........................................      $ 37,873,949
         Future production costs......................................       (11,222,661)
         Future development costs.....................................        (2,971,245)
         Future income tax expense....................................        (7,656,738)
                                                                             -----------
                                                                              16,023,305
      10% annual discount factor......................................       (10,123,246)
                                                                             -----------
      Standardized measure of discounted future cash flows............      $  5,900,059
                                                                             ===========
   Changes in SMOG:
      Oil and gas sales, net of production costs......................      $ (1,432,118)
      Net changes in prices and production costs......................         3,037,917
      Extensions and discoveries......................................           417,346
      Development costs incurred during the period....................           343,094
      Sales of minerals-in-place......................................        (1,492,864)
      Purchases of minerals-in-place..................................           645,315
      Revisions of estimated future development costs.................          (680,110)
      Revisions of previous quantity estimates........................          (388,379)
      Accretion of discount...........................................           755,456
      Changes in production rates, timing and other...................          (204,986)
                                                                             -----------
      Change in present value of future net revenues..................         1,000,671
      Net change in present value of future income taxes..............          (511,862)
                                                                             -----------
                                                                                 488,809
      Balance, beginning of year......................................         5,411,249
                                                                             -----------
      Balance, end of year............................................      $  5,900,059
                                                                             ===========



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                        PIONEER NATURAL RESOURCES COMPANY

                               S I G N A T U R E

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.


                                 PIONEER NATURAL RESOURCES COMPANY




Date: April 3, 2006              By:  /s/  Darin G. Holderness
                                    -------------------------------------------
                                    Darin G. Holderness
                                    Vice President and Chief Accounting Officer




                                       13




                       PIONEER NATURAL RESOURCES COMPANY

                                 EXHIBIT INDEX



Exhibit No.        Desription
-----------        ----------

   2.1             Purchase and Sale Agreement  by and between Pioneer as Seller
                   and  Marubeni  as  Purchaser  (incorporated  by  reference to
                   Exhibit 2.1 to the Company's Current Report on Form 8-K, File
                   No.  1-13245,   filed  with   the  Securities  and   Exchange
                   Commission on February 28, 2006).

 99.1(a)           News Release dated March 28, 2006.



-------------
(a) Filed herewith.




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