EXHIBIT 5.1

                     MORRISON COHEN SINGER & WEINSTEIN, LLP
                              750 Lexington Avenue
                            New York, New York 10022
                           Telephone: (212) 735-8600
                           Facsimile: (212) 735-8708

                                       January 27, 2000

Enzo Biochem, Inc.
60 Executive Boulevard
Farmingdale, New York 11735

    RE: REGISTRATION STATEMENT ON FORM S-8

Gentlemen:

    In our capacity as counsel to Enzo Biochem, Inc., a New York corporation
(the "Company"), we have been requested to render this opinion in connection
with a registration statement on Form S-8 (the "Registration Statement") being
filed by the Company with the Securities and Exchange Commission under the
Securities Act of 1933, as amended, covering an aggregate of 38,951 shares (the
"Shares") of common stock, $.01 par value per share (the "Common Stock"), of the
Company issuable upon the exercise of certain stock options (the "Options")
granted or to be granted under the Company's 1994 Stock Option Plan (the
"Plan").

    In furnishing our opinion, we have examined the Certificate of
Incorporation, as amended, of the Company, and such other instruments and
documents as we have deemed relevant and necessary as the basis for our opinion
expressed herein. We have examined originals or certified, conformed, or
photostatic copies of all documents, the authenticity of which has been
established to our satisfaction. In all such examinations, we have assumed the
genuineness of all signatures on original and certified documents, and the
conformity to executed documents of all executed copies submitted to us as
conformed or photostatic copies.

    Based upon and subject to the foregoing, we are of the opinion that the
Shares issuable upon exercise of the Options have been duly authorized and, when
paid for and issued in accordance with the terms of the Options, will be duly
and validly issued shares of Common Stock.

    We hereby consent to use of this opinion as an exhibit to the Registration
Statement.

                                   Very truly yours,
                                   /s/ MORRISON COHEN SINGER & WEINSTEIN, LLP
                                   Morrison Cohen Singer & Weinstein, LLP