January 20, 2000



Mark L. Weinstein, President & Chief Executive Officer
Bio-Imaging Technologies, Inc.
826 Newtown-Yardley Road
Newtown, PA 18940-1721

Dear Mark:

     On behalf of the Board of Directors of Bio-Imaging Technologies, Inc., (the
Company),  I am pleased to extend your employment as the Company's President and
Chief Executive Officer and provide you with the following  compensation package
effective February 1, 2000 for a period of two years.

     a)   Base Salary.   You will be  paid an  annual  base  salary of  $190,000
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          payable in bi-weekly installments.  Such base salary shall be reviewed
          at the end of each 12-month  period of employment and any  adjustments
          to be made shall be determined by the Board of Directors at that time.

     b)   Bonuses.  You will be eligible for and may receive bonuses, the amount
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          of which are to be  determined  by the Board of  Directors in its sole
          discretion.

     c)   Incentive  Compensation.  You will be  eligible  for  awards  from the
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          Company's  incentive  compensation  plans on a basis commensurate with
          your position and responsibility.

     d)   Stock Options.  Upon the effective date hereof, you will be granted an
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          option to purchase up to 150,000 shares of Common Stock of the Company
          at a  purchase  price  equal to 100% of the fair  market  value of the
          Common Stock or $0.63, whichever is greater, on the date of the grant,
          which  options  shall vest as  follows:  37,500 on the date hereof and
          37,500 on each of the first,  second and third anniversary of the date
          of the grant. This stock option grant is in addition to existing stock
          option grants.

     e)   Expenses. Subject to and in accordance with the Company's policies and
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          procedures, you are hereby authorized to incur, and, upon presentation
          of itemized  accounts,  shall be reimbursed for any and all reasonable
          and necessary  business-related  expenses, which expenses are incurred
          by you on behalf of the Company.


<PAGE>

     g)   Benefits.  You and your  dependents  shall be  included in any and all
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          plans,  programs and policies which provide benefits for employees and
          their dependents. Such plans, programs and policies may include health
          care   insurance,   long-term   disability   plans,   life  insurance,
          supplemental   disability  insurance,   supplemental  life  insurance,
          holidays and other  similar or comparable  benefits made  available to
          Company employees.

     h)   Absences. You will be entitled to absences because of illness or other
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          incapacity,  and such other  absences,  whether for holiday,  personal
          time,  or for  any  other  purpose,  as  set  forth  in the  Company's
          employment manual or current policies and procedures,  as the case may
          be. You will be entitled to four weeks per year of vacation  time,  to
          be taken consistent with the policies of the Company and the effective
          discharge of your duties.  You will also have the right to  accumulate
          such vacation  time from year to year as specified by current  Company
          policies and procedures.

     You will continue to be subject to all of the Company's  other policies and
procedures,  including,  without limitation,  the requirement that you execute a
copy  of the  attached  form of (1)  Invention  Assignment  and  Confidentiality
Agreement  and (2)  Non-Competition  Agreement.  Eighteen  (18) months into this
two-year  agreement,  the Board of Directors will give an initial  indication in
writing of their intended actions as it relates to your employment status at the
end of the two-year term. Your employment  relationship  with the Company may be
terminated  by the Company upon your death,  disability  (defined as 180 days of
disability in a one-year period, whether or not such days are continuous) or for
cause (as hereinafter defined).  For purposes of this letter, "cause" is defined
as:

            "The Company may terminate the Employee's  employment  hereunder for
     cause  immediately  and with  prompt  notice to the  Employee,  which cause
     shall be  determined  in good  faith  solely  by  the  Board of  Directors.
     'Cause'  for  termination  shall  include,  but  is  not  limited  to,  the
     following conduct of the Employee:
     (1)  Material breach of any  provision of this  Agreement by the  Employee,
          which breach shall not have been cured by the  Employee  within thirty
          (30) days of receipt of written notice of said breach;
     (2)  Misconduct  as an employee of the Company,  including  but not limited
          to: (i)  misappropriating  any funds or property of the Company;  (ii)
          attempting   to  willfully   obtain  any  personal   profit  from  any
          transaction  in which the Employee has an interest which is adverse to
          the interests of the Company; or (iii) any other act or omission which
          substantially  impairs the  Company's  ability to conduct its ordinary
          business in its usual manner;
     (3)  Unreasonable  neglect or refusal to perform the duties assigned to the
          Employee under or pursuant to this Agreement;
     (4)  Conviction of a felony; or
     (5)  Any other act or  omission  which  subjects  the Company or any of its
          subsidiaries to substantial public disrespect, scandal or ridicule."


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<PAGE>

     Notwithstanding  the term of this letter  agreement,  if you are terminated
other than for cause or upon  death or  disability,  you will be paid  severance
equal to six months salary at your then current annual salary.

     You will  also  have the  option  to  lease a car to be  reimbursed  by the
Company following any profitable  quarter but you would be responsible for lease
payment in any quarter where  profitability is not maintained.  In no case shall
reimbursement exceed $500 per month.


     If you agree with the stated  provisions,  please sign and date both copies
enclosed  and  return  one copy to me.  I will  copy  other  Board  members  and
Corporate Counsel.  When you sign this document,  please provide a copy to Maria
Krauss for her information as well.

                                          Sincerely,




                                          James A. Taylor, Ph.D.



/s/ James A. Taylor       1/20/00            /s/ Mark L. Weinstein     1/20/00
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James A. Taylor, Ph.D.     Date              Mark L. Weinstein          Date





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