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-3 No. 333-44439) of Pioneer Natural Resources
        Company and in the related Prospectus,
(3) Registration Statement (Form S-3 No. 333-42315) of Pioneer Natural Resources
        Company and  Pioneer Natural Resources  USA,  Inc.  and in  the  related
        Prospectus,
(4) Registration Statement (Form S-3 No. 333-39381) of Pioneer Natural Resources
        Company and in the related Prospectus,
(5) Registration Statement (Form S-3 No. 333-84442) of Evergreen Resources, Inc.
        and in the related Prospectus,
(6) 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,
(7) Registration Statement  (Form S-8 No. 333-88438)  pertaining to  the Pioneer
        Natural Resources Company Long-Term Incentive Plan,
(8) Registration Statement  (Form S-8 No. 333-39153)  pertaining to the  Pioneer
        Natural Resources Company Deferred Compensation Retirement Plan,
(9) Registration  Statement (Form S-8  No. 333-39249) pertaining  to the Pioneer
        Natural Resources USA, Inc. Profit Sharing 401(k) Plan,
(10) Registration Statement  (Form S-8  No.  333-35085)  pertaining to  the 1996
        Incentive Plan of Mesa, Inc.,
(11) Registration Statement (Form S-8 No.  333-35087)  pertaining to the Pioneer
        Natural Resources Company Long-Term Incentive Plan,
(12) Registration  Statement (Form  S-8 No. 033-44851-99) pertaining to the 1991
        Stock Option Plan of Mesa Inc.,
(13) Registration Statement (Form S-8 No. 333-35165) pertaining to the Pioneer
        Natural Resources Company Employee Stock Purchase Plan, and
(14) Registration Statement (Form S-8 No.  333-35175) pertaining  to the Pioneer
        Natural  Resources  Company  Stock  Options  and  the  Parker &  Parsley
        Petroleum Company Long-Term Incentive Plan;

of our  reports  dated  February  17,  2005,  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, 2004.


                                                               Ernst & Young LLP


Dallas, Texas
February 17, 2005