EXHIBIT 32.2



                                CERTIFICATION OF
                             CHIEF FINANCIAL OFFICER
                      OF PIONEER NATURAL RESOURCES COMPANY
                         PURSUANT TO 18 U.S.C. ss. 1350


     I, Richard P. Dealy,  Executive Vice President and Chief Financial  Officer
of Pioneer Natural  Resources  Company (the "Company"),  hereby certify that the
accompanying  Quarterly  Report on Form 10-Q for the quarterly period ended June
30, 2005,  and filed with the  Securities  and Exchange  Commission  pursuant to
Section  13(a) of the  Securities  Exchange  Act of 1934 (the  "Report")  by the
Company fully complies with the requirements of that section.

     I further  certify  that the  information  contained  in the Report  fairly
presents,  in all material  respects,  the  financial  condition  and results of
operations of the Company.




                                            /s/ Richard P. Dealy
                                          -------------------------------------
                                  Name:   Richard P. Dealy, Executive Vice
                                          President and Chief Financial Officer
                                  Date:   August 4, 2005