Exhibit 5.1

                                   OPINION OF
                    FRIED, FRANK, HARRIS, SHRIVER & JACOBSON

October 28, 1999

Burlington Resources Inc.
5051 Westheimer, Suite 1400
Houston, TX  77056

Ladies and Gentlemen:

     We are acting as special counsel to Burlington Resources Inc., a
Delaware corporation ("BR"), in connection with the Registration Statement
on Form S-3 (the "Registration Statement"), under the Securities Act of
1933, as amended (the "Securities Act"), relating to the issuance by BR of
up to 38,500,000 shares of common stock of BR ("Common Stock") to be
issuable upon exchange of the exchangeable shares (the "Exchangeable
Shares") of Burlington Resources Canada Inc., an Alberta corporation and a
subsidiary of BR, in connection with the acquisition of Poco Petroleums
Ltd. by BR. Capitalized terms used herein have the meanings set forth in
the Registration Statement, unless otherwise defined herein. With your
permission, all assumptions and statements of reliance herein have been
made without any independent investigation or verification on our part
except to the extent otherwise expressly stated, and we express no opinion
with respect to the subject matter or accuracy of such assumptions or items
relied upon.

     In connection with this opinion, we have (i) investigated such
questions of law, (ii) examined originals, or certified, conformed or
reproduction copies of such agreements, instruments, documents and records
of BR, such certificates of public officials and such other documents, and
(iii) received such information from officers and representatives of BR as
we have deemed necessary or appropriate for the purposes of this opinion.

     In all such examinations, we have assumed the legal capacity of all
natural persons, the genuineness of all signatures, the authenticity of
original and certified documents and the conformity to original or
certified documents of all copies submitted to us as conformed or
reproduction copies. As to various questions of fact relevant to the
opinion expressed herein, we have relied upon, and assume the accuracy of,
representations and warranties contained in the documents relevant hereto
and certificates and oral or written statements and other information of or
from representatives of BR and others and assume compliance on the part of
all parties to such documents with their covenants and agreements contained
therein.

     We have assumed that the certificate of incorporation and by-laws of
BR at the time of issuance of the shares of Common Stock will be identical
to the certificate of incorporation and by-laws of BR as in effect at the
date hereof.

     We also have assumed, with respect to all parties to the documents
relevant hereto other than BR, that such parties have the power and
authority to enter into and perform such documents and to consummate the
transactions contemplated thereby, that such documents have been duly
authorized, executed and delivered by such parties and constitute legal,
valid and binding obligations of such parties enforceable against such
parties in accordance with the terms, and that such parties will comply
with all of their obligations under such documents and all laws applicable
thereto. As to various questions of fact relevant to such opinions, we have
relied upon, and have assumed the accuracy of, certificates and oral or
written statements and other information of or from public officials,
officers or representatives of BR and others.

     Based upon the foregoing and assuming that all of the Exchangeable
Shares are validly issued, fully paid and non-assessable, it is our opinion
that, if shares of Common Stock are issued as described in the Registration
Statement, at such time of issuance such shares of Common Stock will be
validly issued, fully paid and non-assessable.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the Registration Statement as having passed upon the
validity of the issuance of the Common Stock. In giving this consent, we do
not hereby admit that we are in the category of persons whose consent is
required under Section 7 of the Securities Act.

                                 Very truly yours,

                                 FRIED, FRANK, HARRIS SHRIVER & JACOBSON

                                 By: /s/ Warren de Wied
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                                     Warren de Wied