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                                                                       Exhibit 5


                       [Letterhead of Dilworth Paxson LLP]

DIRECT DIAL NUMBER:
215-575-7000

                                November 21, 2000


The Board of Directors
Manugistics Group, Inc.
2115 East Jefferson Street
Rockville, MD 20852


               Re:  Shares of Common Stock to be Registered on Form S-4

Dear Sirs:

         We have acted as counsel for Manugistics Group, Inc., a Delaware
corporation (the "Company"), in connection with the preparation of a
Registration Statement on Form S-4 (Reg. No. 333-48952) which the Company filed
on October 30, 2000, with the Securities and Exchange Commission pursuant to the
Securities Act of 1933, as amended, relating to up to a total of 4,300,000
shares (the "Shares") of the Company's common stock, par value $.002 per share,
which the Company will issue in connection with its pending acquisition of Talus
Solutions, Inc., pursuant to a certain Agreement and Plan of Merger dated as of
September 21, 2000, by and among the Company, Talus Solutions, Inc. and the
Company's direct, wholly-owned subsidiary, Manu Acquisition Corp. (the "Merger
Agreement"). (The form of said Registration Statement, including all exhibits
thereto and all documents incorporated therein by reference, as amended by
Amendment No. 1 dated November 21, 2000, is referred to below as the
"Registration Statement.")

         A total of 3,505,597 of the Shares may be resold from time to time for
the account of certain persons of the Company who are referred to in the
Registration Statement as the "Selling Stockholders." The Company will issue
such Shares to the Selling Stockholders pursuant to the Merger Agreement.

         In this connection, we have examined: (i) the Company's Amended and
Restated Certificate of Incorporation and Amended and Restated By-laws, as
presently in effect; (ii) the resolutions and related minutes of the Company's
Board of Directors approving the Merger Agreement and the transactions
contemplated thereby, including the issuance of the Shares and approving the
preparation and filing of the Registration Statement; (iii) the Merger
Agreement; (iv) the Registration Statement; and (v) certain officers'
certificates and such other documents as we have deemed appropriate or necessary
for purposes of rendering the opinion hereinafter expressed.


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Dilworth Paxson LLP                                                       Page 2
To: The Board of Directors


         In rendering the opinion expressed below, we have assumed the
authenticity of all documents and records examined, the conformity with the
original documents of all documents submitted to us as copies and the
genuineness of all signatures.

         Based upon and subject to the foregoing, we are of the opinion that the
Shares are duly authorized, and, when issued at closing pursuant to the Merger
Agreement, will be legally issued, fully paid and non-assessable.

         We are admitted to practice in the Commonwealth of Pennsylvania. We
have made such investigation of the General Corporation Law of the State of
Delaware (the "Delaware GCL") as we have considered appropriate for the purpose
of rendering the opinions expressed above. This opinion is limited to the
Federal law of the United States and the Delaware GCL.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference made to this Firm under the caption
"Legal Matters" in the Prospectus constituting a part of the Registration
Statement.

                                                    Sincerely,

                                                    /s/ Dilworth Paxson LLP

                                                    DILWORTH PAXSON LLP