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                                                                     EXHIBIT 8.1

                      [ANDREWS & KURTH L.L.P. LETTERHEAD]

March 21, 2001

The Williams Companies, Inc.
One Williams Center
Tulsa, Oklahoma 74172

Ladies and Gentlemen:

          We have acted as counsel for The Williams Companies, Inc., a Delaware
corporation (the "Company"), in connection with the filing by the Company with
the Securities and Exchange Commission of a Registration Statement on Form S-4
(the "Registration Statement") with respect to (i) the issuance by the Company
of up to $700,000,000 aggregate amount of its 7.50% Debentures due January 15,
2031, Series A (the "Exchange Debentures"), registered pursuant to the
Registration Statement under the Securities Act of 1933, as amended (the
"Securities Act"), in exchange for up to $700,000,000 aggregate amount of the
Company's outstanding 7.50% Debentures due January 15, 2031 (the "Outstanding
Debentures") and (ii) the issuance by the Company of up to $400,000,000
aggregate amount of its 6.75% Putable Asset Term Securities (PATS)
Putable/Callable January 15, 2006, Series A (the "Exchange PATS"), registered
pursuant to the Registration Statement under the Securities Act, in exchange for
up to $400,000,000 aggregate amount of the Company's outstanding 6.75% Putable
Asset Term Securities (PATS) Putable/Callable January 15, 2006 (the "Outstanding
PATS"). The Exchange Debentures are to be issued pursuant to an Indenture dated
as of November 10, 1997, as amended by the Fifth Supplemental Indenture dated as
of January 17, 2001 between the Company and Bank One Trust Company, N.A., as
Trustee. The Exchange PATS are to be issued pursuant to an Indenture dated as of
November 10, 1997, as amended by the Fourth Supplemental Indenture dated as of
January 17, 2001 between the Company and Bank One Trust Company, N.A., as
Trustee.

         Subject to the limitations and qualifications set forth below, we are
of the opinion that the description of federal income tax consequences appearing
under the heading "United States Federal Tax Considerations" in the prospectus
contained in the Registration Statement accurately describes the material
federal income tax consequences to holders of Outstanding Debentures,
Outstanding PATS, Exchange Debentures and Exchange PATS under existing law and
subject to the qualifications and assumptions stated therein.

         The opinion herein is based upon our interpretations of current 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
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The Williams Companies, Inc.
March 21, 2001
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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 consent to the use and filing of this opinion as Exhibit 8.1 to the
Registration Statement and to the reference to our firm under the caption
"United States Federal Tax Considerations" and "Legal Matters" in the prospectus
contained therein. In giving such consent we do not imply or admit that we are
within the category of persons whose consent is required under Section 7 of the
1933 Act or the rules and regulations of the Securities and Exchange Commission
thereunder.

                                              Very truly yours,


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



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