EXHIBIT 5.1

                               February ___, 2002

Devon Financing Corporation, U.L.C.
Devon Energy Corporation
20 North Broadway, Suite 1500
Oklahoma City, Oklahoma 73102

         Re:  Registration Statement on Form S-4
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Ladies and Gentlemen:

         We have acted as special counsel for Devon Financing Corporation,
U.L.C. (the "Company") and Devon Energy Corporation. (the "Guarantor") in
connection with the preparation of a registration statement on Form S-4 (the
"Registration Statement") being filed with the Securities and Exchange
Commission relating to the registration of the Company's 6.875% Notes due 2011
(the "Notes") and its 7.875% Debentures due 2031 (the "Debentures," and together
with the Notes, the "Securities") and the unconditional guarantees as to the
payment of principal and interest on the Securities by the Guarantor (the
"Guarantees"). Pursuant to the Registration Statement, the Company is offering
to exchange (the "Exchange Offer") up to $1,750,000,000 aggregate principal
amount of the Notes for a like amount of its outstanding 6.875% Notes due 2011
(the "Original Notes") and up to $1,250,000,000 aggregate principal amount of
the Debentures for a like amount of its outstanding 7.875% Debentures due 2031
(the "Original Debentures", and together with the Original Notes, the "Original
Securities") and to exchange the Guarantees for the unconditional guarantees as
to the payment of principal and interest on the Original Securities by the
Guarantor (the "Original Guarantees"). The Securities and the Guarantees will be
issued upon consummation of the Exchange Offer. The Original Securities and
Original Guarantees were, and the Securities and the Guarantees will be, issued
pursuant to an indenture, dated as of October 3, 2001 (as amended, the
"Indenture") among the Company, the Guarantor and The Chase Manhattan Bank, as
trustee (the "Trustee").

         In our capacity as counsel to the Company and the Guarantor we have
examined (i) the Registration Statement, (ii) the Indenture and (iii) the
originals, or copies identified to our satisfaction, of such corporate records
of the Company and the Guarantor, certificates of public officials, officers of
the Company and the Guarantor, and other persons, and such other documents,
agreements and instruments as we have deemed necessary as a basis for the
opinions hereinafter expressed.

         In our examination, we have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, conformed or photostatic copies and the
authenticity of the originals of such latter documents. As to any facts material
to the opinions expressed herein which were not independently established or
verified, we have relied upon oral or written statements and representations of
officers and other representatives of the Company and the Guarantor and others.



     Our opinion set forth below is limited to the laws of the State of New
York, the General Corporation Law of the State of Delaware and the federal laws
of the United States and we do not express any opinion herein concerning any
other laws.

     Based on the foregoing, and having regard for such legal considerations as
we have deemed relevant, we are of the opinion that when the Securities and the
Guarantees have been duly authorized and executed by the Company and the
Guarantor, respectively, the Securities (to which the Guarantees will be
affixed) have been authenticated by the Trustee in accordance with the
provisions of the Indenture and delivered to holders tendering into the Exchange
Offer in accordance with the terms of the Exchange Offer as set forth in the
Registration Statement, the Securities and the Guarantees will be legally issued
and will constitute valid and binding obligations of the Company and the
Guarantor, respectively, enforceable against the Company and the Guarantor,
respectively, in accordance with their terms.

     The opinion set forth above is subject, as to enforcement, to (i)
bankruptcy, insolvency (including, without limitation, all laws relating to
fraudulent transfers), reorganization, moratorium or other similar laws relating
to or affecting the enforcement of creditors' rights generally, (ii) general
equitable principles (regardless of whether enforcement is considered in a
proceeding in equity or at law) and (iii) provisions of law that require that a
judgment for money damages rendered by a court in the United States be expressed
only in United States dollars.

     In rendering the opinion set forth above, we have assumed that the Company
has complied with all aspects of the laws of its jurisdiction of organization in
connection with the issuance of the Securities.

     We hereby consent to the use of this opinion letter as an exhibit to the
Registration Statement and to the use of our name under the heading "Legal
Matters" in the prospectus included as part of the Registration Statement.

                                       Very truly yours,



                                       MAYER, BROWN, ROWE & MAW



DAS