EXHIBIT 5.1



                                                              September 12, 2007

TETRAGENEX INC
1 Maynard Dr., Suite 205
Park Ridge, NJ 07656

          Re: REGISTRATION STATEMENT ON FORM SB-2 (THE "REGISTRATION STATEMENT")
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Gentlemen:

         You have  requested  our opinion as to the  legality of the issuance by
you (the  "Corporation") of 9,963,128 shares of common stock ("Shares"),  all as
further described in the Registration  Statement filed with the U.S.  Securities
and Exchange Commission on September 12, 2007, as amended.

        As your counsel, we have reviewed and examined:

        1. The Certificate of Incorporation of the Corporation;

        2. The Bylaws of the Corporation;

        3. A copy of certain resolutions of the corporation; and

        4. The Registration Statement to be filed

         In giving  our  opinion,  we have  assumed  without  investigation  the
authenticity of any document or instrument  submitted to us as an original,  the
conformity  to the original of any document or  instrument  submitted to us as a
copy, and the genuineness of all signatures on such originals or copies.

         Based upon the  foregoing,  we are of the opinion that the Shares to be
offered  pursuant to the  Registration  Statement,  if sold as  described in the
Registration Statement will be legally issued, fully paid and non-assessable.

        No opinion is expressed herein as to the application of state securities
or Blue Sky laws.

         We consent to the reference to our firm name in the Prospectus filed as
a part  of the  Registration  Statement  and  the  use  of  our  opinion  in the
Registration  Statement.  In giving these consents, we do not admit that we come
within the category of persons whose consent is required  under Section 7 of the
Securities and Exchange Commission promulgated thereunder.

                                                 Very truly yours,

                                                 /S/ Gersten Savage LLP

                                                 GERSTEN SAVAGE LLP