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                                                                     EXHIBIT 5.1



August 7, 2001


                  [BROBECK, PHLEGER & HARRISON LLP LETTERHEAD]


i2 Technologies, Inc.
One i2 Place
11701 Luna Road
Dallas, Texas  75234

Re:      i2 Technologies, Inc.
         Registration Statement on Form S-3 (Reg. 333-59106)

Ladies and Gentlemen:

We have acted as counsel to i2 Technologies, Inc., a Delaware corporation (the
"Company"), in connection with the registration under the Securities Act of
1933, as amended (the "Act"), of the sale by a stockholder of the Company of (i)
up to 800,000 shares (collectively, the "Merger Shares") of the Company's common
stock, par value $0.00025 per share ("Common Stock"), and (ii) up to an
aggregate of 1,200,000 shares of Common Stock issuable either (A) pursuant to a
Convertible Promissory Note to be made by the Company (the "Note") and/or (B) to
reimburse the selling stockholder for certain compensation expense tax benefits
the Company may receive in connection with the mergers described below (the
shares of Common Stock issuable under the Note being referred to as the "Note
Shares" and the shares of Common Stock issuable as consideration for the tax
benefits being referred to as the "Tax Benefit Shares"), all of which have been
or may be issued in connection with the transactions contemplated by the Amended
and Restated Agreement and Plan of Reorganization (the "Reorganization
Agreement") by and among the Company, Cowrie One Merger Corp., a California
corporation and wholly owned subsidiary of the Company, Cowrie Two Merger Corp.,
a California corporation and wholly owned subsidiary of the Company, ec-Content
Holdings, LLC, a Delaware limited liability company, Trade Services Holdings,
LLC, a Delaware limited liability company, ec-Content, Inc., a California
corporation, and Trade Service Corporation, a California corporation, pursuant
to the Company's Registration Statement on Form S-3 (the "Registration
Statement") filed with the Securities and Exchange Commission under the Act.

This opinion is being furnished in accordance with the requirements of Item 16
of Form S-3 and Item 601(b)(5)(i) of Regulation S-K.

We have reviewed the Company's charter documents and the corporate proceedings
taken by the Company in connection with the Reorganization Agreement and the
issuance of the Merger Shares, the Note, the Note Shares and the Tax Benefit
Shares. Based on such review, we are of the opinion that (i) the Merger Shares
are duly authorized, validly issued, fully paid and nonassessable, (ii) upon
conversion of the Note pursuant to its terms, the Note Shares will be duly
authorized, validly issued, fully paid and nonassessable and (iii) when and if
issued





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i2 Technologies, Inc.
August 7, 2001
Page 2


pursuant to the Reorganization Agreement, the Tax Benefit Shares will be duly
authorized, validly issued, fully paid and nonassessable.

We consent to the filing of this opinion letter as Exhibit 5.1 to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the prospectus which is part of the Registration Statement.
In giving this consent, we do not thereby admit that we are within the category
of persons whose consent is required under Section 7 of the Act, the rules and
regulations of the Securities and Exchange Commission promulgated thereunder or
Item 509 of Regulation S-K.

This opinion letter is rendered as of the date first written above and we
disclaim any obligation to advise you of facts, circumstances, events or
developments which hereafter may be brought to our attention and which may
alter, affect or modify the opinion expressed herein. Our opinion is expressly
limited to the matters set forth above and we render no opinion, whether by
implication or otherwise, as to any other matters relating to the Company, the
Reorganization Agreement, the Merger Shares, the Note, the Note Shares or the
Tax Benefit Shares.

Very truly yours,


/s/ Brobeck, Phleger & Harrison LLP


BROBECK, PHLEGER & HARRISON LLP