EXHIBIT 5.3

                          (MCINNES COOPER LETTERHEAD)

May 30, 2003


Apache Corporation
2000 Post Oak Boulevard, Suite 100
Houston, TX 77056-4400


Ladies & Gentlemen:

         RE:      FORM S-3 REGISTRATION

         We have acted as Nova Scotia counsel to Apache Corporation (the
"Company") in connection with the preparation of a Registration Statement on
Form S-3 (the "Registration Statement") under the Securities Act of 1933, as
amended (the "Securities Act") relating to the registration of an aggregate of
up to $1,500,000,000 of debt securities (the "Debt Securities") of Apache
Finance Canada II Corporation, an unlimited liability company organized under
the laws of the Province of Nova Scotia, Canada (the "Issuer"), pursuant to a
senior indenture and/or subordinated indenture in the forms filed as Exhibit 4.9
and Exhibit 4.12, respectively, to the Registration Statement (each an
"Indenture" and collectively, the "Indentures") among the JP Morgan Chase Bank,
as Trustee, the Company and the Issuer. We understand that the Debt Securities
issued by the Issuer will be guaranteed by the Company pursuant to a guarantee
provided for under the Indenture.

         We have examined:

         (i)      the Registration Statement covering the Debt Securities which
                  we understand has been filed with the United States Securities
                  and Exchange Commission;

         (ii)     the forms of the Indentures;

         (iii)    the Memorandum of Association and Articles of Association of
                  the Issuer as contained in the minute book of the Issuer made
                  available for our




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                                                                    May 30, 2003

                  inspection on the date hereof, which we assume is complete and
                  accurate in all respects;

         (iv)     a resolution signed by the directors of the Issuer on April
                  30, 2003 with respect to, inter alia, the entering into of the
                  Indentures and the issuance of the Debt Securities, which we
                  assume continues in full force and effect unamended as of the
                  date hereof; and

         (v)      a certificate of status dated May 22, 2003 issued in respect
                  of the Issuer by the Registrar of Joint Stock Companies for
                  the Province of Nova Scotia;

and such other documents and instruments as we deemed necessary or appropriate
for the expression of the opinion contained herein.

     For purposes of giving this opinion, we have assumed the following:

     (a)     the genuineness of all signatures, the authenticity of all
             documents submitted to us as originals and the conformity to
             authentic original documents of all documents submitted to us as
             copies;

     (b)     such documents are within the capacity and powers of, and have been
             validly authorized, executed,and delivered by and are binding on,
             the parties to them other than the Issuer;

     (c)     insofar as any obligation under any document is to be performed in
             any jurisdiction other than in the Province of Nova Scotia, its
             performance will not be illegal or unenforceable under the law of
             that jurisdiction;

     (d)     each such document has been duly executed and delivered and
             constitutes or will constitute legal, valid and binding obligations
             of the parties under their respective governing laws, enforceable
             in competent courts of such jurisdictions; and

     (e)     the information provided by government officials, agencies and
             authorities is complete and accurate.

         Based upon the foregoing and subject to the limitations set forth
below, it is our that, under current law, the Issuer has the corporate power
and authority to issue the Debt Securities and the Debt Securities have been
duly authorized by the Issuer.

         Our opinion herein is limited solely to the laws of the Province of
Nova Scotia and the federal laws of Canada applicable therein  and we express no
opinion herein concerning the law of any other jurisdiction.

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                                                                    May 30, 2003


         While we express no opinion as to enforceability, we point out that the
enforceability of the Debt Securities is subject to the effect of any applicable
bankruptcy, insolvency, fraudulent conveyance, moratorium, reorganization or
similar law affecting creditors' rights or debtors' obligations generally and to
general equity principles, including (without limitation) concepts of
materiality, reasonableness, good faith and fair dealing, and other similar
doctrines affecting the legality and binding nature of obligation or agreements
generally.

         Our opinion herein is rendered solely for your benefit in connection
with the transaction contemplated herein. Our opinion herein may not be used or
relied on by any third party, filed with a government agency, quoted, cited or
otherwise referred to without our prior written consent, except that each of
Chamberlain, Hrdlicka, White, Williams & Martin and Sidley Austin Brown &
Wood LLP, may rely on this letter and the opinion expressed herein as if each of
them were named as an addressee of this letter.

         We hereby consent to the filing of this opinion letter as Exhibit 5.3
to the Registration Statement and to the reference to our name under the caption
"Legal Matters" in the prospectus forming part of the Registration Statement. In
giving such consent, we do not thereby admit that we are in the category of
persons whose consent is required under Section 7 of the Securities Act.


                                             Yours very truly,

                                             /s/ MCINNES COOPER