SecProbe.io

March 6, 2012
 Via E-mail

Anthony S. Chilton President and Chief Executive Officer Bioanalytical Systems, Inc. 2701 Kent Avenue West Lafayette, Indiana 47906
Re: Bioanalytical Systems, Inc.
 Form 10-K
Filed December 29, 2011 File No. 000-23357

Dear Mr. Chilton:
 We have reviewed your filing and have the following comment.  Please respond to this
letter within ten business days by amending your filing or by advising us when you will provide
the requested response.  If you do not believ e 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 filing and the information you provide in
response to this comment, we may have additional comments.
Form 10-K, filed December 29, 2011

Clients, page 6

1. We note that you entered into a Preferred Pr ovider Agreement with Pharmasset, Inc.,
which has become your largest client, and that in 2011 it accounted for 14.5% of your
revenues.  Please revise your disclosure to de scribe the material terms of your agreement
with Pharmasset including, but not limite d to any payment provisions, material
obligations that must be met by both parties to  keep the agreement in place, duration and
termination provisions.  Also, please file the agreement as an exhibit pursuant to Item
601(b)(10) of Regulation S-K.  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 include s the information the Securities Exchange Act of
1934 and all applicable Exchange Act rules requir e.  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.

Anthony S. Chilton Bioanalytical Systems, Inc. March 6, 2012 Page 2

 In responding to our comment, please provide a written statement from the company
acknowledging that:
 the company is responsible for the adequacy an d accuracy of the disclo sure in the filing;

 staff comments or changes to disclosure in response to staff comments do not foreclose
the Commission from taking any action with respect to the filing; and

 the company may not assert staff comments as  a defense in any proceeding initiated by
the Commission or any person under the federa l securities laws of  the United States.

Please contact Johnny Gharib at (202) 551-3170, Jennifer Riegel at (202) 551-3575 or me
at (202) 551-3715 with any questions.
Sincerely,
   /s/ Jennifer Riegel for    Jeffrey Riedler
Assistant Director
 cc: Stephen J. Hackman  Ice Miller LLP  One American Square, Suite 2900
 Indianapolis, IN 46282