EXHIBIT 23.1

            CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the  incorporation  by  reference  in the  following  Registration
Statements:

       (1)    Registration Statement (Form S-3 No. 333-88478) of Pioneer Natural
              Resources Company  and Pioneer Natural Resources  USA, Inc. and in
              the related Prospectus,

       (2)    Registration Statement (Form S-8 No. 333-136488) pertaining to the
              Pioneer Natural Resources Company  Executive Deferred Compensation
              Plan,

       (3)    Registration Statement (Form S-8 No. 333-136489) pertaining to the
              Pioneer Natural Resources Company 2006 Long-Term Incentive Plan,

       (4)    Registration Statement (Form S-8 No. 333-136490) pertaining to the
              Pioneer Natural Resources Company Long-Term Incentive Plan,

       (5)    Registration Statement (Form S-8 No. 333-119355) pertaining to the
              2000 Stock Incentive Plan of Evergreen Resources, Inc., the Carbon
              Energy  Corporation 1999  Stock  Option  Plan,  and the  Evergreen
              Resources, Inc. Initial Stock Option Plan,

       (6)    Registration  Statement (Form S-8 No. 333-88438) pertaining to the
              Pioneer Natural Resources Company Long-Term Incentive Plan,

       (7)    Registration Statement (Form S-8 No. 333-39153)  pertaining to the
              Pioneer Natural Resources Company Deferred Compensation Retirement
              Plan,

       (8)    Registration  Statement (Form S-8 No. 333-39249) pertaining to the
              Pioneer Natural Resources USA, Inc.Profit Sharing 401(k) Plan,

       (9)    Registration Statement (Form  S-8 No. 333-35085) pertaining to the
              1996 Incentive Plan of Mesa, Inc.,

       (10)   Registration Statement (Form S-8 No. 333-35087)  pertaining to the
              Pioneer Natural Resources Company Long-Term Incentive Plan,

       (11)   Registration  Statement (Form S-8 No. 333-35165) pertaining to the
              Pioneer Natural Resources Company Employee Stock Purchase Plan;

of our  reports  dated  February 19,  2007,  with  respect to  the  consolidated
financial  statements of Pioneer  Natural  Resources  Company,  Pioneer  Natural
Resources  Company  management's  assessment  of the  effectiveness  of internal
control over financial reporting, and the effectiveness of internal control over
financial  reporting  of Pioneer  Natural  Resources  Company,  included in this
Annual Report (Form 10-K) for the year ended December 31, 2006.

                                                               Ernst & Young LLP

Dallas, Texas
February 19, 2007