SecProbe.io

January 19, 2012
Via E-Mail
Dr. Michael Bristow President and Chief Executive Officer  ARCA biopharma, Inc. 8001 Arista Place, Suite 430 Broomfield, Colorado 80021
Re: ARCA biopharma, Inc.
  Registration Statement on Form S-3
Filed January 12, 2012
  File Nos. 333-178984

Dear Dr. Bristow:
 We have limited our review of your registra tion statement to those issues we have
addressed in our comments.  In some of our comments, we may ask you to provide us with
information so we may better understand your disclosure.
 Please respond to this letter by amending your registration statement and providing the
requested information.  Where you do not beli eve our comments apply to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.
 After reviewing any amendment to your re gistration statement and the information you
provide in response to these comments, we may have additional comments.

Signatures

1. The registration statement should also be signed by the registrant’s controller or principal
accounting officer.  Any person w ho occupies more than one of the specified positions
required to sign the registration statement should indicate each capacity in which he signs
the registration statement.  See Instru ctions to Signatures to Form S-3.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing incl udes the information the Securities Act of 1933 and
all applicable Securities Act rules require.  Since the company and its management are in
possession of all facts relating to a company’s disc losure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

Dr. Michael Bristow ARCA biopharma, Inc. January 19, 2012 Page 2

 Notwithstanding our comments, in the event you request acceleration of  the effective date
of the pending registration statement please pr ovide a written statement from the company
acknowledging that:

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

 the action of the Commission or the staff, acting pursuant to 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 a nd the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.  Please refer to Rules 460 and 461 regarding re quests for acceleration.  We will consider a
written request for acceleration of  the effective date of the regi stration statement as confirmation
of the fact that those reques ting acceleration are aware of thei r respective responsibilities under
the Securities Act of 1933 and the Securities Excha nge Act of 1934 as they relate to the proposed
public offering of the securities specified in th e above registration stat ement.  Please allow
adequate time for us to review any amendment prior to the requested effective date of the
registration statement.

Please contact John Krug, Senior Counsel, at (202) 551-3862, Dan Greenspan, Branch
Chief, at (202) 551-3623 or me at  (202) 551-3715 with any questions.

Sincerely,
  /s/ Jeffrey Riedler     Jeffrey Riedler
Assistant Director
    cc: Brent D. Fassett, Esquire       Bryn P. Weaver, Esquire       Cooley LLP       300 Interlocken Crescent, Suite 900       Broomfield, Colorado 80021