1
                                                                     Exhibit 5.1

                       [letterhead of Sullivan & Cromwell]



                                                                   June 15, 2001




The Goldman Sachs Group, Inc.,
     85 Broad Street,
        New York, New York 10004.

Ladies and Gentlemen:

                  In connection with the registration under the Securities Act
of 1933 (the "Act") by The Goldman Sachs Group, Inc., a Delaware corporation
(the "Company"), of $11,450,000,000 aggregate amount of its senior and
subordinated debt securities, warrants, purchase contracts, units comprised of
the foregoing, preferred stock and depositary shares representing preferred
stock (collectively, the "Securities"), the shares of Common Stock, par value
$0.01 per share, of the Company (the "Shares") initially issuable upon
conversion, exercise or exchange of any Securities that are convertible into or
exercisable or exchangeable for Shares and the stock purchase rights related to
the Shares (the "Rights") to be issued pursuant to the Stockholder Protection
Rights Agreement, dated as of April 5, 1999, between the Company
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The Goldman Sachs Group, Inc.                                                -2-


and ChaseMellon Shareholder Services, L.L.C., as Rights Agent (the "Rights
Agent"), we, as your counsel, have examined such corporate records, certificates
and other documents, including the resolutions of the Company's board of
directors authorizing the issuance of the Securities (the "Resolutions"), and
such questions of law, as we have considered necessary or appropriate for the
purposes of this opinion.

      Upon the basis of such examination, we advise you that, in our opinion:

      (1) Indenture Securities. The indenture relating to the senior debt
      securities, which is dated as of May 19, 1999, has been duly authorized,
      executed and delivered by the Company, and the indenture relating to the
      subordinated debt securities and the indenture relating to certain of the
      warrants, in the forms filed as exhibits to the Registration Statement,
      have been duly authorized by the Company. When the Registration Statement
      has become effective under the Act, when the indenture relating to the
      subordinated debt securities and the indenture relating to certain of the
      warrants have been duly executed and delivered substantially in the forms
      so filed, when
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The Goldman Sachs Group, Inc.                                                -3-


         the terms of the debt securities or the warrants to be issued under an
         indenture and of their issuance and sale have been duly established in
         conformity with the applicable indenture so as not to violate any
         applicable law or result in a 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 when the debt securities or
         such warrants have been duly executed and authenticated in accordance
         with the applicable indenture and issued and sold as contemplated in
         the Registration Statement, and if all the foregoing actions are taken
         pursuant to the authority granted in the Resolutions, the debt
         securities and such warrants will constitute valid and legally binding
         obligations of the Company, subject to bankruptcy, insolvency,
         fraudulent transfer, reorganization, moratorium and similar laws of
         general applicability relating to or affecting creditors' rights and to
         general equity principles, and the Shares, when duly issued upon
         conversion, exercise or exchange of any such Securities
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The Goldman Sachs Group, Inc.                                                -4-


         that are convertible into or exercisable or exchangeable for Shares,
         will be validly issued, fully paid and nonassessable. The debt
         securities covered by the opinion in this paragraph include any debt
         securities that may be issued as part of the units or upon exercise or
         otherwise pursuant to the terms of any other Securities, as well as any
         purchase contracts or units that may be issued under the indentures
         relating to the debt securities. The warrants covered by the opinion in
         this paragraph include any warrants issued under an indenture that may
         be issued as part of the units or upon exercise or otherwise pursuant
         to the terms of any other Securities.

                  (2) Warrants Not Issued Under an Indenture. When the
         Registration Statement has become effective under the Act, when the
         terms of the warrant agreements under which certain of the warrants are
         to be issued have been duly established and the warrant agreements have
         been duly executed and delivered, when the terms of such warrants and
         of their issuance and sale have been duly established in conformity
         with the applicable warrant agreement and when such warrants have been
         duly
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The Goldman Sachs Group, Inc.                                                -5-


         executed and authenticated in accordance with the applicable warrant
         agreement and issued and sold as contemplated in the Registration
         Statement, and if all the foregoing actions are taken pursuant to the
         authority granted in the Resolutions and so as not to violate any
         applicable law or result in a 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, such warrants will constitute
         valid and legally binding obligations of the Company, subject to
         bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium
         and similar laws of general applicability relating to or affecting
         creditors' rights and to general equity principles, and the Shares,
         when duly issued upon conversion, exercise or exchange of any such
         warrants that are convertible into or exercisable or exchangeable for
         Shares, will be validly issued, fully paid and nonassessable. The
         warrants covered by the opinion in this paragraph include any warrants
         that may be issued as part of the units or upon exercise or
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The Goldman Sachs Group, Inc.                                                -6-


         otherwise pursuant to the terms of any other Securities, but they do
         not include any warrants to be issued under the indenture relating to
         certain of the warrants.

                  (3) Purchase Contracts Not Issued Under an Indenture. When the
         Registration Statement has become effective under the Act, when the
         terms of the governing instruments or agreements under which certain of
         the purchase contracts are to be issued have been duly established and
         the governing documents have been duly executed and delivered, when the
         terms of such purchase contracts and of their issuance and sale have
         been duly established in conformity with the applicable governing
         documents and when such purchase contracts have been duly executed and
         authenticated in accordance with the applicable governing documents and
         issued and sold as contemplated in the Registration Statement, and if
         all the foregoing actions are taken pursuant to the authority granted
         in the Resolutions and so as not to violate any applicable law or
         result in a default under or breach of any agreement or instrument
         binding upon the Company and so as to comply with any requirement or
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The Goldman Sachs Group, Inc.                                                -7-


         restriction imposed by any court or governmental body having
         jurisdiction over the Company, such purchase contracts will constitute
         valid and legally binding obligations of the Company, subject to
         bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium
         and similar laws of general applicability relating to or affecting
         creditors' rights and to general equity principles, and the Shares,
         when duly issued upon conversion, exercise or exchange of any such
         purchase contracts that are convertible into or exercisable or
         exchangeable for Shares, will be validly issued, fully paid and
         nonassessable. The purchase contracts covered by the opinion in this
         paragraph include any purchase contracts that may be issued as part of
         the units or upon exercise or otherwise pursuant to the terms of any
         other Securities, but they do not include any purchase contracts to be
         issued under the indentures relating to the debt securities.

                  (4) Units Not Issued Under an Indenture. When the Registration
         Statement has become effective under the Act, when the terms of the
         unit agreements under which certain of the units are to be issued have
         been
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The Goldman Sachs Group, Inc.                                                -8-


         duly established and the unit agreements have been duly executed and
         delivered, when the terms of such units and of their issuance and sale
         have been duly established in conformity with the applicable unit
         agreements and when such units have been duly executed and
         authenticated in accordance with the applicable unit agreements and
         issued and sold as contemplated in the Registration Statement, and if
         all the foregoing actions are taken pursuant to the authority granted
         in the Resolutions and so as not to violate any applicable law or
         result in a 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, such units will constitute valid and
         legally binding obligations of the Company, subject to bankruptcy,
         insolvency, fraudulent transfer, reorganization, moratorium and similar
         laws of general applicability relating to or affecting creditors'
         rights and to general equity principles. The units covered by the
         opinion in this paragraph include any units that may be issued upon
         exercise or
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The Goldman Sachs Group, Inc.                                                -9-


         otherwise pursuant to the terms of any other Securities, but they do
         not include any units to be issued under the indentures relating to the
         debt securities.

                  (5) Preferred Stock. When the Registration Statement has
         become effective under the Act, when the terms of the preferred stock
         and of its issuance and sale have been duly established in conformity
         with the Company's certificate of incorporation so as not to violate
         any applicable law or result in a 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, when an
         appropriate certificate of designations with respect to the preferred
         stock has been duly filed with the Secretary of State of the State of
         Delaware and when the preferred stock has been duly issued and sold as
         contemplated by the Registration Statement, and if all the foregoing
         actions are taken pursuant to the authority granted in the Resolutions,
         the preferred stock will be validly issued, fully paid and non-
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The Goldman Sachs Group, Inc.                                               -10-

         assessable, and the Shares, when duly issued upon conversion, exercise
         or exchange of any preferred stock that is convertible into or
         exercisable or exchangeable for Shares, will be validly issued, fully
         paid and nonassessable. The preferred stock covered in the opinion in
         this paragraph includes any preferred stock that may be represented by
         depositary shares or may be issued upon exercise or otherwise pursuant
         to the terms of any other Securities.

                  (6) Depositary Shares. When the Registration Statement has
         become effective under the Act, when the terms of the deposit agreement
         under which the depositary shares are to be issued have been duly
         established and the deposit agreement has been duly executed and
         delivered, when the terms of the depositary shares and of their
         issuance and sale have been duly established in conformity with the
         deposit agreement, when the preferred stock represented by the
         depositary shares has been duly delivered to the depositary and when
         the depositary receipts evidencing the depositary shares have been duly
         issued against deposit of the preferred stock in accordance with the
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The Goldman Sachs Group, Inc.                                               -11-


         deposit agreement and issued and sold as contemplated by the
         Registration Statement, and if all the foregoing actions are taken
         pursuant to the authority granted in the Resolutions and so as not to
         violate any applicable law or result in a 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, the depositary
         receipts evidencing the depositary shares will be validly issued and
         will entitle the holders thereof to the rights specified in the
         depositary shares and the deposit agreement, subject to bankruptcy,
         insolvency, fraudulent transfer, reorganization, moratorium and similar
         laws of general applicability relating to or affecting creditors'
         rights and to general equity principles. The depositary shares covered
         by the opinion in this paragraph include any depositary shares that may
         be issued upon exercise or otherwise pursuant to the terms of any other
         Securities.

                  (7) Assuming that the Rights Agreement has been duly
         authorized, executed and delivered by the Rights
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The Goldman Sachs Group, Inc.                                               -12-


         Agent, then when the Registration Statement has become effective under
         the Act and the Shares have been validly issued upon conversion,
         exercise or exchange of any Securities that are convertible into or
         exercisable or exchangeable for Shares, the Rights attributable to the
         Shares will be validly issued.

                  In connection with our opinion set forth in paragraph (7)
above, we note that the question whether the Board of Directors of the Company
might be required to redeem the Rights at some future time will depend upon the
facts and circumstances existing at that time and, accordingly, is beyond the
scope of such opinion.

                  We note that, as of the date of this opinion, a judgment for
money in an action based on a Security denominated in a foreign currency or
currency unit in a Federal or state court in the United States ordinarily would
be enforced in the United States only in United States dollars. The date used to
determine the rate of conversion of the foreign currency or currency unit in
which a particular Security is denominated into United States dollars will
depend upon various factors, including which court renders the judgment. In the
case of a Security
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The Goldman Sachs Group, Inc.                                               -13-


denominated in a foreign currency, a state court in the State of New York
rendering a judgment on such Security would be required under Section 27 of the
New York Judiciary Law to render such judgment in the foreign currency in which
the Security is denominated, and such judgment would be converted into United
States dollars at the exchange rate prevailing on the date of entry of the
judgment.

                  The foregoing opinion is limited to the Federal laws of the
United States, the laws of the State of New York and the General Corporation Law
of the State of Delaware, and we are expressing no opinion as to the effect of
the laws of any other jurisdiction.

                  We have relied as to certain matters on information obtained
from public officials, officers of the Company and other sources believed by us
to be responsible. We have assumed, without independent verification, that the
indenture relating to the senior debt securities and the indenture relating to
certain of the warrants have been duly authorized, executed and delivered by the
trustee thereunder, and that all other governing documents under which the
Securities are to be issued, as well as the purchase contracts, if applicable,
will have been duly
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The Goldman Sachs Group, Inc.                                               -14-


authorized, executed and delivered by all parties thereto other than the Company
and that the signatures on documents examined by us are genuine. We have further
assumed that the issuance or delivery by the Company of any securities other
than the Securities, or of any other property, upon exercise or otherwise
pursuant to the terms of the Securities will be effected pursuant to the
authority granted in the Resolutions and so as not to violate any applicable law
or result in a default under or breach of any agreement or instrument binding on
the Company and so as to comply with any requirement or restriction imposed by
any court or governmental body having jurisdiction over the Company. Finally, we
have assumed that the authority granted in the Resolutions will remain in effect
at all relevant times.

                  We are expressing no opinion as to any obligations that
parties other than the Company may have under or in respect of the Securities or
as to the effect that their performance of such obligations may have upon any of
the matters referred to above.

                  We hereby consent to the filing of this opinion as an exhibit
to the Registration Statement and to the
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The Goldman Sachs Group, Inc.                                               -15-


reference to us under the heading "Validity of the Securities" in the
Prospectus. 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 Act.

                                                     Very truly yours,

                                                     /s/ Sullivan & Cromwell