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                                                                     EXHIBIT 5.1


                                  June 30, 2000




Kerr-McGee Corporation
Kerr-McGee Center
Oklahoma City, Oklahoma 73125

         Re:      FORM S-8 REGISTRATION STATEMENT COVERING SECURITIES
                  ISSUABLE UNDER THE EXECUTIVE DEFERRED COMPENSATION PLAN

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
Corporation, a Delaware corporation ("Company") to be registered with the
Securities and Exchange Commission on a Form S-8 Registration Statement
("Registration Statement") and issuable pursuant to the Kerr-McGee Corporation
Executive Deferred Compensation Plan ("Plan").

         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 Plan, 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 Plan 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,


                                      Gregory F. Pilcher


GFP/kdh