EXHIBIT 10.6
                                 Amendment No. 5
                                       to

                        PIONEER NATURAL RESOURCES COMPANY

                            LONG-TERM INCENTIVE PLAN


     AMENDMENT NO. 5 (this "Amendment") to that certain Long-Term Incentive Plan
(the "Plan") of Pioneer Natural  Resources  Company (the "Company") is effective
as of May 12, 2004.  Terms  having  their  initial  letter  capitalized  but not
defined in this Amendment have the meaning ascribed those terms in the Plan.

                                    RECITALS

     WHEREAS,  on August 7, 1997, the  stockholders of the Company  approved the
adoption of the Plan and the stock of the  Company was then and is still  listed
for trading on the New York Stock Exchange: and

     WHEREAS, the Board of Directors of the Company has approved an amendment to
the Plan, which amendment is memorialized below in this Amendment.

     NOW, THEREFORE, the Plan is hereby amended as follows:


     1. Section 1.3 of the Plan is hereby  amended by adding  "Restricted  Stock
Units" to the definition of "Award".

     2. Section 1.37(a) is hereby added to the Plan as follows:

        "Restricted Stock Unit"  means the grant of a right to receive shares of
     Stock in  the future,  on the  terms  and  conditions  that  the  Committee
     determines,  with shares  of Stock subject to a risk of forfeiture or other
     restrictions that  will lapse  upon the  achievement of  one or  more goals
     relating to completion  of service by the  Participant,  or  achievement of
     performance or other objectives, as determined by the Committee."

     IN WITNESS WHEREOF, the Company has caused this Amendment to be executed by
its duly authorized officer to be effective as of May 12, 2004.

                                        PIONEER NATURAL RESOURCES COMPANY


                                        By:   /s/ Mark L. Withrow
                                            -----------------------------------
                                            Name:  Mark L. Withrow
                                            Title: Executive Vice President and
                                                   General Counsel