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                             Andrews & Kurth L.L.P.
                             600 Travis, Suite 4200
                              Houston, Texas 77002
                                                                  Exhibit 8.1(a)
                                   May 7, 2001


Anadarko Petroleum Corporation
17001 Northchase Drive
Houston, Texas 77060-2141

Ladies and Gentlemen:

         We have acted as counsel to Anadarko Petroleum Corporation (the
"Company") in connection with the preparation and filing of a Registration
Statement on Form S-3 (the "Registration Statement") pursuant to the Securities
Act of 1933, as amended (the "Securities Act"), relating to the registration for
resale under the Securities Act of $650,000,000 aggregate issue price of the
Company's Zero Yield Puttable Contingent Debt Securities (ZYP-CODES(sm)) due
2021 (the "ZYP-CODES") which may be converted in certain cases into shares of
the Company's common stock.

         In connection with our opinion we have reviewed the Registration
Statement, including the exhibits thereto, and such other documents, records and
instruments as we have deemed necessary or appropriate for purposes of this
opinion. In such examination, we have assumed the genuiness 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 copies, and the
authenticity of the originals of such documents submitted as copies.

         Based upon and subject to the foregoing and the qualifications set
forth herein and in reliance thereon, we are of the opinion that the discussion
set forth in the Registration Statement under the heading "Certain United States
Federal Income Tax Considerations" accurately describes the material United
States federal income tax consequences to holders of ZYP-CODES under existing
United States laws and subject to the qualifications and assumptions stated
therein.

         The opinion set forth above is based upon our interpretations of
current United States federal income tax law, including court authority and
existing Final and Temporary Regulations, which are subject to change both
prospectively and retroactively, and upon the facts and assumptions discussed
herein. No opinion is being rendered as to the amount of the comparable yield
for the ZYP-CODES. In addition, our opinion is based on the assumption that the
matter will be properly presented to the applicable court. Furthermore, our
opinion is not binding on the Internal Revenue Service or a court. In addition,
we must note that our opinion represents merely our best legal judgment on the
matters presented and that others may disagree with our conclusion. There can be
no assurance that the Internal Revenue Service will not take a contrary position
or that a court would agree with our opinion if litigated.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the use of our name under the heading "Certain
United States Federal Income Tax Considerations" in the Registration Statement.
In giving this consent, we do not thereby admit that we are included in the
category of persons whose consent is required under Section 7 of the Securities
Act or the rules
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Anadarko Petroleum Corporation
May 7, 2001
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and regulations promulgated thereunder. This opinion is intended solely for your
use as an exhibit to the Registration Statement for the purpose of the above
sale of ZYP-CODES or common stock and is not to be relied upon for any other
purpose.

                                                  Very truly yours,

                                                  /s/ ANDREWS & KURTH L.L.P.

                                                  Andrews & Kurth L.L.P.

1568/1216/2606