SecProbe.io

October 6 , 2014

Via E -mail
Isaac E. Ciechanover, M.D.
Chief Executive Officer
Atara Biotherapeutics, Inc.
3260 Bayshore Boulevard
Brisbane, CA 94005

Re: Atara Biotherapeutics, Inc.
Amendment No. 2 to
Registration Statement on Form S -1
Filed  September 26 , 2014
  File No. 333-196936

Dear Dr. Ciechanover:

We have reviewed your amendment to your r egistration statement  and have the following
comment .  Please respond to this letter by amending your registration statement and providing
the requested information.   If you do not believe our comment applies  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 registration statement and the information you
provide in response to this comment , we may have additional comments.

Notes to Combined and Consolidated Financial Statements
2. Summary of Significant Accounting Policies
Recent Accounting Pronouncements, F -19

1. Regarding your adoption of ASU 2014 -10, your disclosure appears to indicate that
certain consolidation guidance that has been eliminated by the ASU may have caused
more development stage entities to be identified as variable interest entities.   Please
provide us support for this disclosure with reference to the ASU.

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing i ncludes 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 disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

Isaac E. Ciechanover, M.D.
Atara Biotherapeutics, Inc.
October 6 , 2014
Page 2

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

 should the Commis sion 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 to delegated autho rity, 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 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 requests for acceleration.  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of thei r 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 securities specified in the above registration statement.  Please allow
adequate time for us to rev iew any amendment prior to the requested effective date of the
registration statement.

You may contact Vanessa Robertson at (202) 551 -3649  or James Rosenberg  at (202)
551-3679  if you have questions regarding comments on the financial statements and related
matters.  Please contact Daniel Greenspan at (202) 551 -3623  or me at (202) 551 -3715 with any
other questions.

Sincerely,

 /s/ Daniel Greenspan  for

Jeffrey P. Riedler
Assistant Director

cc: Via E -mail
 Jodie Bourdet , Esq.
 Cooley  LLP