FIRST AMENDMENT TO
CREDIT AGREEMENT

         THIS FIRST AMENDMENT made as of the        day of May, 2003, by and
between BIOANALYTICAL SYSTEMS, INC. (“Borrower”) and THE PROVIDENT BANK
("Bank");

W I T N E S S E T H:

         WHEREAS, as of October 29, 2002, the parties hereto entered into a
certain Credit Agreement (the “Agreement”); and

        WHEREAS, the parties desire to amend the Agreement to revise certain of
the financial covenants, subject to the terms contained herein;

        NOW, THEREFORE, in consideration of the premises, and the mutual
promises herein contained, the parties agree that the Agreement shall be, and it
hereby is, amended as provided herein and the parties further agree as follows:

PART I.    AMENDATORY PROVISIONS

Section 5.    Covenants

        5.3.         Financial Covenants.

          5.3.1.         Funded Debt Ratio.    Section 5.3.1 of the Agreement is
hereby amended by substituting the following new Section 5.3.1 in lieu of the
existing Section 5.3.1:

          5.3.1.         Funded Debt Ratio.    Maintain its Funded Debt Ratio at
not greater than (a) 3.75 to 1.00 at each fiscal quarter ending through and
including December 31, 2003, (b) 3.50 to 1.00 as of March 31, 2004 and June 30,
2004, (c) 3.00 to 1.00 as of September 30, 2004, (b) 2.50 to 1.00 as of
December 31, 2004 and at each fiscal quarter ending thereafter through and
including September 30, 2005, and (c) 2.00 to 1.00 as of December 31, 2005 and
as of each fiscal quarter ending thereafter.

PART II.    EXHIBIT

        Except as expressly modified herein:

          (a)         All terms, conditions, representations, warranties and
covenants contained in the Agreement shall remain the same and shall continue in
full force and effect, interpreted, wherever possible, in a manner consistent
with this First Amendment; provided, however, in the event of any irreconcilable
inconsistency, this First Amendment shall control;

SIGNATURE PAGE OF
BIOANALYTICAL SYSTEMS, INC.
TO FIRST AMENDMENT TO CREDIT AGREEMENT

  “BORROWER”

BIOANALYTICAL SYSTEMS, INC.

By:  

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Its:  

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SIGNATURE PAGE OF
THE PROVIDENT BANK
TO FIRST AMENDMENT TO CREDIT AGREEMENT

  “BANK”

THE PROVIDENT BANK

By:  

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Its:  

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PARTICIPANT’S CONSENT

        The undersigned, the “Participant” under that certain Participation
Agreement dated as of October 29, 2002 between the The Provident Bank (the
“Bank”) and the undersigned, hereby consents to the execution and delivery by
the Bank and Bioanalytical Systems, Inc. of the attached First Amendment to
Credit Agreement and further consents to the terms contained therein. The
undersigned further agrees that the obligations of the undersigned under the
Participation Agreement are hereby ratified, confirmed and reaffirmed in all
respects.

        IN WITNESS WHEREOF, the undersigned has caused this Consent to be
executed by its officer duly authorized as of the        day of May, 2003.

  FIFTH THIRD BANK, INDIANA

By:  

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Its:  

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