EXHIBIT 23.1



            Consent of Independent Registered Public Accounting Firm



We consent to the incorporation by reference in the Registration Statement (Form
S-8 No. 333-39249)  pertaining to the Pioneer Natural Resources USA, Inc. 401(k)
and  Matching  Plan of our  report  dated  May 18,  2006,  with  respect  to the
financial  statements  and schedule of the Pioneer  Natural  Resources USA, Inc.
401(k) and Matching Plan included in this Annual Report (Form 11-K) for the year
ended December 31, 2005.


                                                     Ernst & Young LLP


Dallas, Texas
June 23, 2006










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