EXHIBIT 10.12

                                 AMENDMENT NO. 3
                                     TO THE
          PIONEER NATURAL RESOURCES USA, INC. 401(k) AND MATCHING PLAN
          ------------------------------------------------------------

     Pursuant to the  provisions  of Section 8.1  thereof,  the Pioneer  Natural
Resources  USA, Inc.  401(k) and Matching Plan (the "Plan") is hereby amended in
the following respects only:

     FIRST:  Effective  January 1, 2002,  Section  1.1(kk) of the Plan is hereby

amended by restatement in its entirety to read as follows:

             (kk) "Pre-Tax Account" means the account established and maintained
     under this Plan by the Committee to record a  Participant's  interest under
     this  Plan  attributable  to  (i)  Pre-Tax  Contributions,   Pre-Tax  Bonus
     Contributions and Catch-Up  Contributions  made by an Employer on behalf of
     such  Participant  and (ii) any  amounts  credited  to his or her  Employee
     Pre-Tax  Contribution  Account  under the  Superseded  Plan as in effect on
     September 30, 1997.

     SECOND:  Effective  January 1, 2003,  Section  3.1(e) of the Plan is hereby

amended  by  restating  the last  sentence  thereof in its  entirety  to read as

follows:

     If any portion of a Pre-Tax  Contribution or Pre-Tax Bonus  Contribution is
     distributed or recharacterized pursuant to this subsection,  any portion of
     a Matching  Contribution  (along with any income allocable thereto) made to
     this  Plan  for  such   Participant   that  matches  the   distributed   or
     recharacterized Pre-Tax Contribution or Pre-Tax Bonus Contribution shall be
     forfeited.

     THIRD: Effective January 1, 2003, Section 3.2 of the Plan is hereby amended

by restatement in its entirety to read as follows:

     Section 3.2  Matching Contributions.

             (a) For each pay period an Employer shall make to the Plan for each
     Participant in its employ a Matching  Contribution  equal to 200 percent of
     the Pre-Tax Contributions made by the Employer on such Participant's behalf
     during  such pay  period  which are not in excess of five  percent  of such
     Participant's Basic Compensation for such pay period.

             (b) As of the end of each Plan Year,  an Employer shall make to the
     Plan for each  Participant  in its employ on the last day of such Plan Year
     an additional Matching Contribution equal to A minus B, where A is equal to
     200 percent multiplied by the lesser of (i) the Participant's Total Pre-Tax





     Contributions  for the Plan Year or (ii) five percent of the  Participant's
     Basic Compensation for the Plan Year, and B is equal to the total amount of
     Matching  Contributions made for the Participant for the Plan Year pursuant
     to Section 3.2(a).

             (c) The Committee shall  establish and maintain an Employer Account
     for each  Participant.  All Matching  Contributions  made for a Participant
     pursuant to this Section shall be credited to such  Participant's  Employer
     Account.

     FOURTH:  Effective  January  1,  2002,  Section  3.3 of the Plan is  hereby

amended to add the following new sentence to the end thereof:

     All Catch-Up  Contributions  made by an Employer on behalf of a Participant
     pursuant  to this  Section  3.1  shall be  credited  to such  Participant's
     Pre-Tax Account.

     FIFTH: Effective January 1, 2003, Section 3.5 of the Plan is hereby amended

by restatement in its entirety to read as follows:

             Section 3.5 Payment of Contributions. Pre-Tax Contributions, Catch-
     Up  Contributions  and  After-Tax  Contributions  made  to the  Plan  by an
     Employer for or on behalf of Participants for a pay period shall be paid to
     the Trustee in cash as soon as practicable  after such pay period ends, but
     no later  than the 15th  business  day  after the end of the month in which
     such pay  period  ends.  Pre-Tax  Bonus  Contributions  made to the Plan on
     behalf  of  Participants  shall be paid to the  Trustee  in cash as soon as
     practicable after the bonus payment is made, but no later than the 15th day
     of the month  after the end of the month in which  such  bonus  payment  is
     made. Matching  Contributions made to the Plan for a pay period pursuant to
     Section 3.2(a) shall be paid to the Trustee as soon as practicable,  but no
     later  than 30 days  after  the end of the month in which  such pay  period
     ends.  Matching  Contributions made to the Plan for a Plan Year pursuant to
     Section  3.2(b)  shall  be paid to the  Trustee  no  later  than  the  time
     prescribed by law,  including  extensions  thereof,  for the filing of such
     Employer's federal income tax return for such year.

     SIXTH:  Effective  January 1, 2003,  the last sentence of Section 3.7(b) is

hereby amended by restatement in its entirety to read as follows:

     If any portion of a Pre-Tax Contribution or Pre-Tax Bonus Contribution made
     by  an  Employer  on  behalf  of  a  Participant  is  distributed  to  such
     Participant  or is  treated  as a  Catch-Up  Contribution  pursuant  to the
     foregoing  provisions  of this  subsection  (b),  any portion of a Matching
     Contribution  (along  with  any  income  allocable  thereto)  made for such


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     Participant  that matches the distributed  Pre-Tax  Contribution or Pre-Tax
     Bonus  Contribution  or  recharacterized  Catch-Up  Contribution  shall  be
     forfeited.

     SEVENTH: Effective July 30, 2002, Section 6.9 of the Plan is hereby amended

to add a new subsection to the end thereof to read as follows:

             (d) Plan loans to  directors and executive  officers of an Employer
         may be denied in the event that the Committee determines that loans may
         not be  made to such  persons under  the Sarbanes-Oxley  Act of 2002 or
         other federal law.

     EIGHTH:  Effective  January  1,  2003,  Section  10.3 of the Plan is hereby

amended by restating the last three sentences  thereof in their entirety to read

as follows:

     Any  Matching  Contributions   corresponding  to  any  distributed  Pre-Tax
     Contributions  and  Pre-Tax  Bonus  Contributions  shall be  credited  to a
     suspense  account and  thereafter  reallocated  (prior to the allocation of
     subsequent  forfeitures and the making of any additional  contributions  to
     the Plan) to reduce  the  earliest  subsequent  Matching  Contributions  an
     Employer  would  otherwise  be  required  to make to the Plan  pursuant  to
     Section 3.2 for such year and the next  succeeding Plan Year. No adjustment
     shall be made to such  suspense  account to  reflect  income,  profits  and
     losses,  expenses or other  transactions  affecting  the Plan.  Any Pre-Tax
     Contributions or Pre-Tax Bonus  Contributions  distributed to a Participant
     pursuant to this  Section  shall not be taken into  account in  determining
     such Participant's actual deferral percentage for purposes of Section 3.7.

     IN WITNESS  WHEREOF,  this  Amendment has been executed on this 16th day of

June, 2003.

                                     PIONEER NATURAL RESOURCES USA, INC.




                                     By   /s/ Larry Paulsen
                                        --------------------------------
                                         Larry Paulsen, Vice President



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