Filed Pursuant to Rule 424(b)(3)
                                                     Registration No. 333-134302

Prospectus Supplement No. 4
to Prospectus dated June 14, 2006


                                  AVITAR, INC.

                                28,000,000 Shares
                                  Common Stock

     We are  supplementing  the  prospectus  dated  June  14,  2005  to  provide
information  contained  in our  Current  Report  on  Form  8-K  filed  with  the
Securities  and  Exchange   Commission  on  October 27,  2006  including  the
following:

OTHER EVENTS

     On August 16, 2006, a Complaint was filed in United States  District Court,
District of New Jersey, by Sun Biomedical Laboratories, Inc., Plaintiff, against
Avitar Technologies,  Inc., Defendant,  a wholly-owned  subsidiary of Avitar. In
the Complaint, Plaintiff alleged among other things breaches of contract, patent
infringement  and unfair  competition  and it seeks damages and  injunctions.  A
Summons in this case was not issued until September 22, 2006 and the Summons was
not delivered to Avitar until October 13, 2006.

     The  alleged  breach of contract  is based upon an  agreement  made in 1999
related to the  development  of products  and sales of goods.  The last  invoice
issued to the Defendant was sent by Plaintiff in August 2002. In September 2002,
Avitar  advised the Plaintiff  that the Defendant  owes nothing to the Plaintiff
and that the Plaintiff would owe substantial amounts for its failures to perform
in accordance with their agreement.

     Based upon a  preliminary  evaluation  of this  lawsuit,  it  appears  that
certain claims are likely barred by the applicable  statute of limitations  and,
in the Company's  view,  the remainder of the claims are  substantially  without
merit. Further assessment will be made upon ongoing evaluation. In the meantime,
the  Company  intends  to defend  the suit  vigorously  and to put  forward  all
appropriate counterclaims.

     This  Prospectus  Supplement  is  not  complete  without,  and  may  not be
delivered or utilized except in connection  with, the Prospectus  dated June 14,
2006,  with  respect to the  resale of the  28,000,000  shares of common  stock,
including any amendments or supplements thereto.

     INVESTING  IN OUR COMMON STOCK  INVOLVES A HIGH DEGREE OF RISK.  YOU SHOULD
READ CAREFULLY THIS ENTIRE  PROSPECTUS,  INCLUDING THE SECTION  CAPTIONED  "RISK
FACTORS" BEGINNING ON PAGE 3, BEFORE MAKING A DECISION TO PURCHASE OUR STOCK.

     NEITHER THE  SECURITIES AND EXCHANGE  COMMISSION  NOR ANY STATE  SECURITIES
COMMISSION HAS APPROVED OR  DISAPPROVED  OF THESE  SECURITIES OR PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.


                The date of this Supplement is October 27, 2006