Exhibit 5



                                 July 31, 2001


Kerr-McGee Holdco, Inc.
123 Robert S. Kerr Avenue
Oklahoma City, Oklahoma 73125


     Re:  Form S-8 Registration Statement Covering Securities Issueable Under
          the Oryx Energy Company 1997 Long Term Incentive Plan, Oryx Energy
          Company Executive Variable Incentive Plan and Oryx Energy Company
          Equity and Deferred Compensation Plan for Non-Employee Directors

Gentlemen:

          You have requested my advice with respect to the legality of the
shares of Common Stock, par value $1.00 per share ("Common Stock"), of
Kerr-McGee Holdco, Inc., a Delaware corporation (the "Company"), to be
registered with the Securities and Exchange Commission on a Form S-8
Registration Statement ("Registration Statement") and issuable pursuant to the
Oryx Energy Company 1997 Long Term Incentive Plan, Oryx Energy Company
Executive Variable Incentive Plan and Oryx Energy Company Equity and Deferred
Compensation Plan for Non-Employee Directors (the "Plans").

          In connection with the foregoing request, I or a member of my staff,
have examined the Registration Statement, the Company's Certificate of
Incorporation and Bylaws, as amended to date, corporate minutes, the Plans,
and such other documents and records as I deem necessary to render the
opinions contained herein. I have assumed the genuineness of all signatures
and conformity to original documents of copies of such documents. As to any
facts relevant to my opinion, I have relied upon information given to me by
the Officers of the Company and Others.

          Based on the foregoing, it is my opinion that:

          1.   The Company is in good standing under the laws of the State of
               Delaware.

          2.   The authorized but unissued shares of Common Stock being
               registered pursuant to the Registration Statement have been
               duly authorized by the Company and will, upon being issued
               under the Plans as described in the Registration Statement, be
               validly issued, fully paid and nonassessable.

          I consent to the use of this opinion as an exhibit to the captioned
Registration Statement.

                                  Sincerely,

                                  /s/ Gregory F. Pilcher

                                  Gregory F. Pilcher
                                  Senior Vice President
                                  General Counsel and Secretary