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): February 22, 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 1.01.  Entry into a Material Definitive Agreement................    3

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

            (d)   Exhibits............................................    3

Signature.............................................................    4

Exhibit Index.........................................................    5




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                        PIONEER NATURAL RESOURCES COMPANY



Item 1.01.    Entry into a Material Definitive Agreement

     On February 22, 2006,  Pioneer Natural Resources USA, Inc.  ("Pioneer"),  a
wholly-owned  subsidiary of Pioneer Natural  Resources  Company,  entered into a
Purchase and Sale Agreement (the  "Agreement")  through which Marubeni  Offshore
Production (USA) Inc. ("Marubeni"),  a subsidiary of Marubeni Corporation,  will
acquire certain  deepwater Gulf of Mexico assets (the "Assets") from Pioneer for
$1.3 billion.  The effective time of the purchase and sale  contemplated  by the
Agreement  is  January 1, 2006,  and the  purchase  price will be reduced by the
amount of the interim  period cash flow that  Pioneer  receives  from the Assets
between the effective date of the  transaction  and closing.  The transaction is
subject to the exercise of preferential  rights related to certain of the Assets
by the holders of those rights.  The closing of the  transaction  is expected to
occur in March or April  2006 and is subject to  customary  closing  conditions,
including the expiration or  termination of the applicable  waiting period under
the Hart-Scott-Rodino Antitrust Improvements Act of 1976.

     The  description  of the  Agreement  set forth  above is  qualified  in its
entirety by reference to the Agreement, which is filed as an exhibit to this
report and incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits

      (d)  Exhibits

           2.1  Purchase and Sale Agreement by and between Pioneer as Seller and
                Marubeni as Purchaser  (pursuant to the  rules of the Securities
                sand Exchange Commission (the "Commission"),  the  schedules and
                similar  attachments  to  the  Agreement  have  not  b een filed
                herewith. The registrant agrees to furnish supplementally a copy
                of any omitted  schedule or  attachment  to the  Commission upon
                request.).




                                        3





                        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: February 28, 2006          By: /s/ Darin G. Holderness
                                    --------------------------------------
                                     Darin G. Holderness
                                     Vice President and Chief Accounting Officer




                                        4




                       PIONEER NATURAL RESOURCES COMPANY

                                 EXHIBIT INDEX


Exhibit No.     Description
-----------     -----------

2.1(a)          Purchase and Sale Agreement by and between Pioneer as Seller and
                Marubeni as Purchaser  (pursuant to the rules of the Commission,
                the schedules and similar attachments to the  Agreement have not
                been  filed   herewith.   The  registrant   agrees  to   furnish
                supplementally a  copy of any omitted  schedule or attachment to
                the Commission upon request.).


-------------
(a) filed herewith






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