Exhibit 5.1

                [Letterhead of Cadwalader, Wickersham & Taft LLP]


                                                               November 18, 2003


Cosi, Inc.
242 West 36th Street
New York, NY 10018

      Re:   Registration Statement on Form S-1

Ladies and Gentlemen:

      You have requested our opinion, as counsel to Cosi, Inc., a Delaware
corporation (the "Company"), in connection with the preparation and filing of a
Registration Statement on Form S-1 (Registration No. 333-107689), as amended
(the "Registration Statement"), with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act").

      The Registration Statement relates to the offering by the Company of
shares of the Company's Common Stock, par value $0.01 per share, issuable upon
the exercise of subscription rights (the "Common Stock") at a maximum aggregate
offering price of $9,583,473 (collectively, the "Shares").

      We have examined such records and documents and made such examinations of
law as we have deemed relevant in connection with this opinion. Based upon such
examinations, it is our opinion that (when there has been compliance with the
Act and the applicable state securities laws) (i) the issuance of the Shares in
accordance with the Registration Statement has been duly authorized by the
Company and (ii) the Shares, when thereafter issued against payment therefor in
connection with the offering, will be validly issued, fully paid and
non-assessable.

      We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the Registration Statement. In doing so, we do not admit that
we are in the category of persons whose consent is required under Section 7 of
the Act or the rules and regulations of the Commission promulgated thereunder.



                                         Very truly yours,

                                         /s/ Cadwalader, Wickersham & Taft LLP