(LETTERHEAD OF CAHILL GORDON & Reindel)


                                                              April 29, 2002







Burlington Resources Inc.
5051 Westheimer, Suite 1400
Houston, TX  77056-2124

Burlington Resources Capital I
c/o Burlington Resources Inc.
5051 Westheimer, Suite 1400
Houston, TX  77056-2124

Burlington Resources Capital II
c/o Burlington Resources Inc.
5051 Westheimer, Suite 1400
Houston, TX  77056-2124

Burlington Resources Finance Company
c/o Burlington Resources Inc.
5051 Westheimer, Suite 1400
Houston, TX  77056-2124

     Re: Registration Statement on Form S-3

Ladies and Gentlemen:

     We have acted as special U.S. counsel to Burlington Resources Inc., a
Delaware corporation (the "Company") and to Burlington Resources Capital I and
Burlington Resources Capital II, each a statutory business trust formed under
Delaware law (each, a "Trust") and Burlington Resources Finance Company, an
unlimited liability company organized under the laws of Nova Scotia, Canada
("Finance



                                      -2-


Company", and together with the Company and the Trusts, the "Registrants") in
connection with the Registration Statement on Form S-3 (the "Registration
Statement"), filed by the Registrants with the Securities and Exchange
Commission. The Registration Statement relates to the issuance and sale from
time to time, pursuant to Rule 415 of the rules and regulations promulgated
under the Securities Act of 1933, as amended (the "Act"), of the following
securities with an aggregate initial offering price of up to $1,500,000,000, as
shall be designated by the Registrants: (i) senior debt securities of the
Company, in one or more series (the "Senior Debt Securities"), which are to be
issued under a senior indenture proposed to be executed between the Company and
Citibank, N.A., as Trustee (the "Senior Indenture"), the form of which is filed
as an exhibit to the Registration Statement, (ii) subordinated debt securities
of the Company, in one or more series (the "Subordinated Debt Securities"),
which are to be issued under a subordinated indenture proposed to be executed
between the Company and Citibank, N.A., as Trustee (the "Subordinated
Indenture"), the form of which is filed as an exhibit to the Registration
Statement, (iii) shares of common stock of the Company, par value $.01 per share
(the "Common Stock"), (iv) shares of preferred stock of the Company (the
"Preferred Stock"), (v) securities issued by each Trust in the form of trust
preferred securities (the "Trust Preferred Securities"), which are proposed to
be issued under the applicable declaration of trust pursuant to which such Trust
is organized (each, as amended and restated prior to such issuance, in the form
of which is filed as an exhibit to the Registration Statement, a "Declaration of
Trust"), (vi) guarantees by the Company of the Trust Preferred Securities (the
"Trust Guarantees") pursuant to a guarantee agreement (each, a "Trust Guarantee
Agreement"), the form of which is filed as an exhibit to the Registration
Statement, (vii ) debt securities of Finance Company (the "Finance Debt
Securities"), which are to be issued under the Indenture between Finance Company
and Citibank, N.A., as Trustee dated as of February 12, 2001 (the "Finance
Indenture"), which is filed as an exhibit to the Registration Statement and
(viii) guarantees of the Company of the Finance Debt Securities (the "Finance
Guarantees") pursuant to the Guarantee Agreement by and between the Company and
Citibank, N.A., as Trustee, dated as of February 12, 2001 (the "Finance
Guarantee Agreement"), which is filed as an exhibit to the Registration
Statement. The Senior Debt Securities, the Subordinated Debt Securities, the
Common Stock, the Preferred Stock, the Trust Preferred Securities, the Trust
Guarantees, the Finance Debt Securities and the Finance Guarantees are referred
to collectively as the "Securities" and individually as a "Security".

     In connection with this opinion, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of such corporate
records, documents, certificates and instruments as we deemed necessary and
appropriate to enable us to render the opinion expressed below.

     In our examination, we have assumed (a) the authenticity of original
documents and the genuineness of all signatures, (b) the conformity to the
originals of all documents submitted to us as copies, (c) the truth, accuracy
and completeness of the information, representations and warranties contained in
the records, documents, instruments and certificates we have reviewed and (d)
the due authorization, execution and delivery of each document named below by
each party other than the Company.



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     We advise you that, in our opinion:

          (a) With respect to the shares of Common Stock, when (i) the
     Registration Statement, as finally amended (including all necessary
     post-effective amendments), has become effective under the Act; (ii) an
     appropriate prospectus supplement or term sheet with respect to the Common
     Stock has been prepared, delivered and filed in compliance with the Act and
     the applicable rules and regulations promulgated thereunder; (iii) if the
     Common Stock is to be sold pursuant to a firm commitment underwritten
     offering, an underwriting agreement with respect to the Common Stock has
     been duly authorized, executed and delivered by the Company and the other
     parties thereto; (iv) the Board of Directors, including any appropriate
     committee appointed thereby, and appropriate officers of the Company have
     taken all necessary corporate action to approve the issuance of the Common
     Stock and related matters; (v) the terms of the issuance and sale of the
     Common Stock have been duly established in conformity with the Certificate
     of Incorporation and the By-laws of the Company so as not to violate any
     applicable law, the Certificate of Incorporation or the By-laws of the
     Company or result in default under or breach of any agreement or instrument
     binding upon the Company and so as to comply with any requirement or
     restriction imposed by any court or governmental body having jurisdiction
     over the Company; and (vi) certificates representing the shares of Common
     Stock have been duly executed, countersigned, registered and delivered upon
     payment of the agreed-upon consideration therefor (provided that such
     consideration is not less than the par value thereof), the shares of Common
     Stock (including any Common Stock duly issued upon conversion of any other
     Security), when issued and sold in accordance with the applicable
     underwriting agreement or any other duly authorized, executed and delivered
     valid and binding purchase or agency agreement, will be duly authorized,
     validly issued, fully paid and nonassessable.

          (b) With respect to the shares of Preferred Stock, when (i) the
     Registration Statement, as finally amended (including all necessary
     post-effective amendments), has become effective under the Act; (ii) an
     appropriate prospectus supplement or term sheet with respect to the
     Preferred Stock has been prepared, delivered and filed in compliance with
     the Act and the applicable rules and regulations promulgated thereunder;
     (iii) if the Preferred Stock is to be sold pursuant to a firm commitment
     underwritten offering, an underwriting agreement with respect to the
     Preferred Stock has been duly authorized, executed and delivered by the
     Company and the other parties thereto; (iv) the Board of Directors,
     including any appropriate committee appointed thereby, and appropriate
     officers of the Company have taken all necessary corporate action to
     approve the issuance and terms of the Preferred Stock and related matters,
     including the adoption of a Certificate of Designation for the Preferred
     Stock in accordance with the applicable provisions of Delaware law (the
     "Certificate of Designation"); (v) the filing of the Certificate of
     Designation with the Secretary of State of the State of Delaware has duly
     occurred; (vi) the terms of the Preferred Stock and of their issuance and
     sale have been duly established in conformity with the Company's
     Certificate of Incorporation, including the Certificate of Designation
     related to the Preferred Stock, and the By-laws of the Company so as not to
     violate any applicable law, the Certificate of Incorporation or the By-laws
     of the Company or result in default under or breach of

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     any agreement or instrument binding upon the Company and so as to comply
     with any requirement or restriction imposed by any court or governmental
     body having jurisdiction over the Company; and (vii) certificates
     representing the shares of Preferred Stock have been duly executed,
     countersigned, registered and delivered upon payment of the agreed-upon
     consideration therefor (provided that such consideration is not less than
     the par value thereof), the shares of Preferred Stock (including any
     Preferred Stock duly issued upon conversion of any other Security), when
     issued and sold in accordance with the applicable underwriting agreement or
     any other duly authorized, executed and delivered valid and binding
     purchase or agency agreement, will be duly authorized, validly issued,
     fully paid and nonassessable.

          (c) With respect to the Senior Debt Securities, when (i) the
     Registration Statement, as finally amended (including all necessary
     post-effective amendments), has become effective under the Act; (ii) the
     Senior Indenture has been duly authorized, executed and delivered by the
     Company and the other parties thereto and duly qualified under the Trust
     Indenture Act of 1939, as amended (the "TIA"); (iii) an appropriate
     prospectus supplement or term sheet with respect to the Senior Debt
     Securities has been prepared, delivered and filed in compliance with the
     Act and the applicable rules and regulations promulgated thereunder; (iv)
     if the Senior Debt Securities are to be sold pursuant to a firm commitment
     underwritten offering, an underwriting agreement with respect to the Senior
     Debt Securities has been duly authorized, executed and delivered by the
     Company and the other parties thereto; (v) the Board of Directors,
     including any appropriate committee appointed thereby, and appropriate
     officers of the Company have taken all necessary corporate action to
     approve the issuance and terms of the Senior Debt Securities and related
     matters; (vi) the terms of the Senior Debt Securities and their issuance
     and sale have been duly established in conformity with the Senior Indenture
     so as not to violate any applicable law, the Certificate of Incorporation
     or the By-laws of the Company or result in default under or breach of any
     agreement or instrument binding upon the Company and so as to comply with
     any requirement or restriction imposed by any court or governmental body
     having jurisdiction over the Company; and (vii) the Senior Debt Securities
     have been duly executed and authenticated in accordance with the provisions
     of the Senior Indenture and duly delivered to the purchasers thereof upon
     payment of the agreed-upon consideration therefor, the Senior Debt
     Securities, when issued and sold in accordance with the provisions of the
     Senior Indenture and in accordance with the applicable underwriting
     agreement, if any, or any other duly authorized, executed and delivered
     valid and binding purchase or agency agreement, will constitute valid and
     binding obligations of the Company enforceable against the Company in
     accordance with their terms, except as enforcement thereof may be limited
     by (a) bankruptcy, insolvency, reorganization, fraudulent conveyance or
     transfer, moratorium or other laws now or hereafter in effect related to or
     affecting creditors' rights generally and (b) general principles of equity
     (regardless of whether enforceability is considered in a proceeding at law
     or in equity).

          (d) With respect to the Subordinated Debt Securities, when (i) the
     Registration Statement, as finally amended (including all necessary
     post-effective amendments), has become effective under the Act; (ii) the
     Subordinated Indenture has been duly authorized, executed and



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     delivered by the Company and the other parties thereto and duly qualified
     under the TIA; (iii) an appropriate prospectus supplement or term sheet
     with respect to the Subordinated Debt Securities has been prepared,
     delivered and filed in compliance with the Act and the applicable rules and
     regulations promulgated thereunder; (iv) if the Subordinated Debt
     Securities are to be sold pursuant to a firm commitment underwritten
     offering, an underwriting agreement with respect to the Subordinated Debt
     Securities has been duly authorized, executed and delivered by the Company
     and the other parties thereto; (v) the Board of Directors, including any
     appropriate committee appointed thereby, and appropriate officers of the
     Company have taken all necessary corporate action to approve the issuance
     and terms of the Subordinated Debt Securities and related matters; (vi) the
     terms of the Subordinated Debt Securities and their issuance and sale have
     been duly established in conformity with the Subordinated Indenture so as
     not to violate any applicable law, the Certificate of Incorporation or the
     By-laws of the Company or result in default under or breach of any
     agreement or instrument binding upon the Company and so as to comply with
     any requirement or restriction imposed by any court or governmental body
     having jurisdiction over the Company; and (vii) the Subordinated Debt
     Securities have been duly executed and authenticated in accordance with the
     provisions of the Subordinated Indenture and duly delivered to the
     purchasers thereof upon payment of the agreed-upon consideration therefor,
     the Subordinated Debt Securities, when issued and sold in accordance with
     the provisions of the Subordinated Indenture and in accordance with the
     applicable underwriting agreement, if any, or any other duly authorized,
     executed and delivered valid and binding purchase or agency agreement, will
     constitute valid and binding obligations of the Company enforceable against
     the Company in accordance with their terms, except as enforcement thereof
     may be limited by (a) bankruptcy, insolvency, reorganization, fraudulent
     conveyance or transfer, moratorium or other laws now or hereafter in effect
     related to or affecting creditors' rights generally and (b) general
     principles of equity (regardless of whether enforceability is considered in
     a proceeding at law or in equity).

          (e) With respect to the Finance Debt Securities, when (i) the
     Registration Statement, as finally amended (including all necessary
     post-effective amendments), has become effective under the Act; (ii) the
     Finance Indenture has been duly qualified under the TIA; (iii) an
     appropriate prospectus supplement or term sheet with respect to the Finance
     Debt Securities has been prepared, delivered and filed in compliance with
     the Act and the applicable rules and regulations promulgated thereunder;
     (iv) if the Finance Debt Securities are to be sold pursuant to a firm
     commitment underwritten offering, an underwriting agreement with respect to
     the Finance Debt Securities has been duly authorized, executed and
     delivered by Finance Company and the other parties thereto; (v) the Board
     of Directors of Finance Company, including any appropriate committee
     appointed thereby, and appropriate officers of Finance Company have taken
     all necessary action to approve the issuance and terms of the Finance Debt
     Securities and related matters; (vi) the terms of the Finance Debt
     Securities and their issuance and sale have been duly established in
     conformity with the Finance Indenture so as not to violate any applicable
     law, the Memorandum and Articles of Association of Finance Company or
     result in default under or breach of any agreement or instrument binding
     upon Finance Company and so as to comply with any requirement or
     restriction imposed by any court or governmental body having jurisdiction
     over Finance



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     Company; and (vii) the Finance Debt Securities have been duly executed and
     authenticated in accordance with the provisions of the Finance Indenture
     and duly delivered to the purchasers thereof upon payment of the
     agreed-upon consideration therefor, the Finance Debt Securities, when
     issued and sold in accordance with the provisions of the Finance Indenture
     and in accordance with the applicable underwriting agreement, if any, or
     any other duly authorized, executed and delivered valid and binding
     purchase or agency agreement, will constitute valid and binding obligations
     of Finance Company enforceable against Finance Company in accordance with
     their terms, except as enforcement thereof may be limited by (a)
     bankruptcy, insolvency, reorganization, fraudulent conveyance or transfer,
     moratorium or other laws now or hereafter in effect related to or affecting
     creditors' rights generally and (b) general principles of equity
     (regardless of whether enforceability is considered in a proceeding at law
     or in equity).

          (f) With respect to the Finance Guarantees, when (i) the Registration
     Statement, as finally amended (including all necessary post-effective
     amendments), has become effective under the Act; (ii) the Finance Guarantee
     Agreement has been duly qualified under the TIA; (iii) an appropriate
     prospectus supplement or term sheet with respect to the Finance Debt
     Securities and the Finance Guarantees has been prepared, delivered and
     filed in compliance with the Act and the applicable rules and regulations
     promulgated thereunder; (iv) the terms of the Finance Debt Securities have
     been established in accordance with the Finance Indenture; (v) the Finance
     Debt Securities have been duly issued and executed in accordance with the
     Finance Indenture and paid for in the manner contemplated in the
     Registration Statement or any prospectus relating thereto; (vi) if the
     Finance Debt Securities and Finance Guarantees are to be sold pursuant to a
     firm commitment underwritten offering, an underwriting agreement with
     respect to such Securities has been duly authorized, executed and delivered
     by Finance Company and the other parties thereto; (vii) the Board of
     Directors, including any appropriate committee appointed thereby, and
     appropriate officers of the Company have taken all necessary corporate
     action to approve the issuance and terms of the Finance Guarantees and
     related matters; (viii) the terms of the Finance Guarantees and of their
     issuance and sale have been duly established in conformity with the Finance
     Guarantee Agreement so as not to violate any applicable law, the
     Certificate of Incorporation or the By-laws of the Company or result in
     default under or breach of any agreement or instrument binding upon the
     Company and so as to comply with any requirement or restriction imposed by
     any court or governmental body having jurisdiction over the Company; and
     (ix) the Finance Guarantees have been duly executed and delivered in
     accordance with the provisions of the Finance Guarantee Agreement, the
     Finance Guarantees, when issued in accordance with the Finance Guarantee
     Agreement, will constitute valid and binding obligations of the Company
     enforceable against the Company in accordance with their terms, except as
     enforcement thereof may be limited by (a) bankruptcy, insolvency,
     reorganization, fraudulent conveyance or transfer, moratorium or other laws
     now or hereafter in effect related to or affecting creditors' rights
     generally and (b) general principles of equity (regardless of whether
     enforceability is considered in a proceeding at law or in equity).



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          (g) With respect to the Trust Guarantees, when (i) the Registration
     Statement, as finally amended (including all necessary post-effective
     amendments), has become effective under the Act; (ii) the applicable Trust
     Guarantee Agreement has been duly authorized, executed and delivered by the
     Company and the other parties thereto and duly qualified under the TIA;
     (iii) an appropriate prospectus supplement or term sheet with respect to
     the Trust Preferred Securities and the Trust Guarantees has been prepared,
     delivered and filed in compliance with the Act and the applicable rules and
     regulations promulgated thereunder; (iv) the Declaration of Trust of the
     applicable Trust has been duly authorized, executed and delivered by the
     parties thereto; (v) the terms of the Trust Preferred Securities have been
     established in accordance with the applicable Declaration of Trust; (vi)
     the Trust Preferred Securities have been duly issued and executed in
     accordance with the applicable Declaration of Trust and paid for in the
     manner contemplated in the Registration Statement or any prospectus
     relating thereto; (vii) if the Trust Preferred Securities and the Trust
     Guarantees are to be sold pursuant to a firm commitment underwritten
     offering, an underwriting agreement with respect to such Securities has
     been duly authorized, executed and delivered by the applicable Trust and
     the other parties thereto; (viii) the Board of Directors, including any
     appropriate committee appointed thereby, and appropriate officers of the
     Company have taken all necessary corporate action to approve the issuance
     and terms of the Trust Guarantees and related matters; (ix) the terms of
     the Trust Guarantees and of their issuance and sale have been duly
     established in conformity with the applicable Trust Guarantee Agreement so
     as not to violate any applicable law, the Certificate of Incorporation or
     the By-laws of the Company or result in default under or breach of any
     agreement or instrument binding upon the Company and so as to comply with
     any requirement or restriction imposed by any court or governmental body
     having jurisdiction over the Company; and (x) the Trust Guarantees have
     been duly executed and delivered in accordance with the provisions of the
     applicable Trust Guarantee Agreement, the Trust Guarantees, when issued in
     accordance with the applicable Trust Guarantee Agreement, will constitute
     valid and binding obligations of the Company enforceable against the
     Company in accordance with their terms, except as enforcement thereof may
     be limited by (a) bankruptcy, insolvency, reorganization, fraudulent
     conveyance or transfer, moratorium or other laws now or hereafter in effect
     related to or affecting creditors' rights generally and (b) general
     principles of equity (regardless of whether enforceability is considered in
     a proceeding at law or in equity).

     In rendering the opinion set forth above, we express no opinion as to the
laws of any jurisdiction other than the laws of the State of New York, the
General Corporation law of the State of Delaware, including the applicable
provisions of the Delaware Constitution and the reported judicial decisions
interpreting such laws, and the federal laws of the United States of America.
The Securities may be issued from time to time on a delayed or continuous basis,
and our opinion is limited to the laws as in effect on the date hereof.

     With respect to opinions (e) and (f) above, we have relied on the opinion
of Stewart McKelvey Stirling Scales dated as of the date hereof, as to the due
organization and valid existence of the Finance Company. With respect to opinion
(g) above, we have relied on the opinion of Richards,



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     Layton & Finger, P.A., dated as of the date hereof, as to the Trusts and
     the validity and legality of the Trust Preferred Securities and related
     documents (other than the Trust Guarantees).

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference of our firm under the caption "Legal
Matters" in the Registration Statement and the prospectus forming a part
thereof. Our consent to such reference does not constitute a consent under
Section 7 of the Act, as in consenting to such reference we have not certified
any part of the Registration Statement and do not otherwise come within the
categories of persons whose consent is required under Section 7 or under the
rules and regulations of the Securities and Exchange Commission thereunder.

                                      Very truly yours,

                                      /s/ Cahill Gordon & Reindel