SecProbe.io

Mail Stop 4720

August 14 , 2015

Via E -mail
Jeffrey Riley
Chief Executive Officer and President
Synthetic Biologics, Inc.
9605 Medical Center Drive, Suite 270
Rockville, Maryland 20850

Re: Synthetic Biologics, Inc.
  Registration Statement on Form S-3
Filed  August 10 , 2015
  File No.  333-206266

Dear Mr. Riley :

This is to advise you that we have not  reviewed and will not review your registration
statement .

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes the information the Securities Act of 193 3 and
all applicable Securities  Act rules require.   Since the company and its management are  in
possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

In the event you request acceleration of the effective date of the pending regist ration
statement , please provide  a written statement from the company acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does not foreclose the Commission from taking any action with respect
to the filing;

 the action of the Commission or the staff, acting pursuant t o delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

 the company may not assert staff comments and the declaration of effect iveness as a
defense in any proceeding initiated by the Commission or any person under the federal
securities laws of the United States.

Jeffrey Riley
Synthetic Biologics, Inc.
August 14 , 2015
Page 2

 Please refer to Rules 460 and 461 regarding requests for  acceleration .  We will consider a
written request for acceler ation of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of their respective responsibilities under
the Securities Act of 1933 and the Securities Exchange Act of 1934 as they relate to the proposed
public offering of the registered securities .

Please contact Christina De Rosa at (202) 551 -3577 or me at (202) 551 -3715 with any
other questions.

Sincerely,

  /s/ Bryan J. Pitko for

 Jeffrey P. Riedler
Assistant Director
Office of  Healthcare and Insurance

cc: Via E -mail
            Leslie Marlow, Esq.
            Gracin & Marlow, LLP
            The Chrysler Building
            405 Lexington Avenue, 26th Floor
            New York, New York 10174