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                                                                     Exhibit 8.1

                                 Andrews & Kurth
                          Mayor, Day & Caldwell L.L.P.
                             600 Travis, Suite 4200
                              Houston, Texas 77002

                                  July 23, 2002

BJ Services Company
5500 Northwest Central Drive
Houston, Texas 77092

     Re:   Registration Statement on Form S-3
           Convertible Senior Notes Due 2022

Ladies and Gentlemen:

     We have acted as counsel to BJ Services Company, a Delaware corporation
(the "Company"), in connection with the issuance by it of $516,350,000 principal
amount of its Convertible Senior Notes due 2022 (the "Notes"), pursuant to an
Indenture, dated as of April 24, 2002 (the "Indenture"), between the Company and
The Bank of New York, as Trustee (the "Trustee"), and in connection with the
preparation and filing with the Securities and Exchange Commission (the
"Commission") of the Registration Statement (as defined below). The Notes and
up to 7,725,422 shares (the "Shares") of common stock, par value $0.10 per
share, issuable upon conversion of the Notes are being registered for resale by
the holders thereof under the Securities Act of 1933, as amended (the "Act")
pursuant to a Registration Statement on Form S-3 (the "Registration Statement").

     In arriving at the opinion expressed below, we have examined (i) the
Registration Statement including the form of prospectus included therein and the
documents incorporated by reference therein, and (ii) the Indenture, and we have
made such investigations of law, as we have deemed appropriate as a basis for
the opinion expressed below.

     In rendering the opinion expressed below, we have assumed and have not
verified (i) the genuineness of the signatures on all documents that we have
examined, (ii) the conformity to the originals of all documents supplied to us
as certified or photostatic or faxed copies, (iii) the authenticity of the
originals of such documents and (iv) as to the forms of all documents in respect
of which forms were filed with the Commission or incorporated by reference as
exhibits to the Registration Statement, the conformity in all material respects
of such documents to the forms thereof that we have examined. In conducting our
examination of documents executed by parties other than the Company, we have
assumed that such parties had the power, corporate or other, to enter into and
perform all obligations thereunder and have also assumed the due authorization
by all requisite action, corporate or other, and the due execution (or, in the
case of the Trustee in respect of the Notes, authentication) and delivery by
such parties of such documents and that such documents constitute valid and
binding obligations of such parties. As to any facts material to the opinion
expressed herein which were not independently established or verified, we have
relied upon oral or written statements and representations of officers,
trustees, and other representatives of the Company and others.

     Subject to the limitations and qualifications set forth herein, we are of
the opinion that the description of the United States federal income tax
consequences appearing under the heading "Certain United States Federal Income
Tax Considerations" in the prospectus contained in the Registration

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Statement accurately describes the material United States federal income
tax consequences to holders of the Notes and the Shares issuable upon conversion
or repurchase of the Notes under existing law 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. This
opinion letter is limited to the matters set forth herein, and no opinions are
intended to be implied or may be inferred beyond those expressly stated herein.
Our opinion is rendered as of the date hereof and we assume no obligation to
update or supplement this opinion or any matter related to this opinion to
reflect any change of fact, circumstances, or law after the date hereof. 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. In giving this consent we do not admit that we are
"experts" under the Act, or the rules and regulations of the Commission issued
thereunder, with respect to any part of the Registration Statement, including
this exhibit. This opinion is rendered solely for your benefit in connection
with the above matter and may not be relied upon in any manner by any other
person or entity without our express written consent.

                                             Very truly yours,



                                             /s/ ANDREWS & KURTH
                                             MAYOR, DAY & CALDWELL L.L.P.