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  report on Form 10-Q for the quarterly period ended March 31, 2005,
and  filed  with the  Securities  and  Exchange  Commission  on the date  hereof
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  aspects,  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: May 6, 2005