Exhibit 5.1


                             Opinion re legality of
                          Dolgenos Newman & Cronin LLP


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                                   EXHIBIT 5.1



                          Dolgenos Newman & Cronin LLP
                  -------------------------------------------------
                     96 Spring Street, New York, N.Y. 10012
                          212-925 2800 Fax 212-925-0690



May 5, 1997



Avitar, Inc.
556 Washington Avenue, Suite 202
North Haven, Connecticut 06473
Tel.: (203) 234-7737



Gentlemen:

We  have  acted  as  counsel  to  Avitar,  Inc.,  a  Delaware  corporation  (the
"Company"),  in  connection  with the Company's  proposed  offering of 1,400,000
shares  of  Common  Stock,   $0.01  par  value  as  described  in  that  certain
Registration  Statement (and the related  Prospectus) on Form S-8 executed today
by the Company and to be filed with the  Securities  and Exchange  Commission on
May 9, 1997 (as amended, the "Registration Statement" and "Prospectus").

In rendering this opinion we have examined copies of the Registration Statement;
the  Company's  Certificate  of  Incorporation,   as  amended,  and  such  other
instruments,   certificates  and  documents  as  we  have  deemed  necessary  or
appropriate for the purpose of rendering this opinion.

In such  examinations,  we have assumed the genuineness of all  signatures,  the
authenticity of all documents submitted to us as originals and the conformity to
original  documents  submitted to us as copies.  We have further assumed for the
purpose of this  opinion  the due  authorization  and,  as  applicable,  the due
execution  and delivery by, or on behalf of, each of the parties  thereto of the
above-referenced  documents and all documents  contemplated by the  Registration
Statement to be executed.

Based on and subject to the foregoing, and limited in all respects to matters of
New York law and the General Corporation Law of the State of Delaware, we are of
the opinion that:

         1.       The Company is a corporation duly organized and validly
                  existing under the laws of the State of Delaware.



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Avitar, Inc.
May 5, 1997
Page 2


         2.       The Company has  authorized  capitalization  of thirty million
                  shares, of which twenty-five  million  (25,000,000) shares are
                  Common Stock,  $0.01 par value,  and five million  (5,000,000)
                  shares are Preferred Stock, $0.001 par value.

         3.       As of the date hereof, 12,077,195 shares of Common Stock
                  have been duly and validly issued and are fully paid
                  and non-assessable.

         4.       The  shares  of  Common  Stock  included  in the  Registration
                  Statement  will,  when issued in accordance with the terms and
                  procedures set forth in the Registration Statement, constitute
                  legally  and  validly  issued,  fully paid and  non-assessable
                  shares of Common Stock.

We  hereby  consent  to  the  filing  of  this  opinion  as  Exhibit  5.1 to the
Registration Statement.


Very truly yours,

DOLGENOS NEWMAN & CRONIN LLP


By: /s/EUGENE M. CRONIN





























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