EXHIBIT 10.31

                            TERMINATION OF AGREEMENT

         This Termination of Agreement, dated as of June 30, 2000, is between
ArQule, Inc. ("ArQule"), a Delaware corporation, and Pharmacia Corporation,
formerly known as Monsanto Company ("Pharmacia"), a Delaware corporation.

                                    RECITALS

         WHEREAS, ArQule and Pharmacia have previously entered into an Array
Delivery and Testing Agreement dated December 23, 1996, as subsequently amended
and restated on January 11, 2000 (the "Prior Agreement"), with respect to which
ArQule provides certain compound arrays for testing by Pharmacia and its
Affiliates and performs certain other compound development activities in
exchange for payment by Pharmacia of research thuds, milestone payments and
royalties; and

         WHEREAS, Pharmacia has decided, and ArQule is willing to, terminate the
Prior Agreement.

         NOW, THEREFORE, in consideration of the mutual covenants set forth in
this Agreement, the parties hereby agree as follows:

         1. Termination. The Prior Agreement previously executed and delivered
by and between ArQule and Pharmacia entitled "Amended and Restated Array
Delivery and Testing Agreement" dated January 2000 (including its predecessor
agreement entitled "Array Delivery and Testing Agreement" dated December 23,
1996, and any other understandings and agreements relating to the subject matter
thereon, and the obligations and rights of the parties with respect thereto,
except as set forth below, are hereby terminated in theft entirety.

         2. Termination Payment. In consideration of the termination of the
Prior Agreement, and the satisfaction and discharge of any and all of
Pharmacia's obligations to make research and development and array delivery
payments thereunder, including without limitation all payments pursuant to
Subsections 3.2.5 and 3.3.2, Pharmacia shall pay to ArQule, within sixty (60)
days following the date hereof, the sum of Four Million One Hundred Thirty Two
Thousand and Five Hundred Ninety Five Dollars (US$4,132,595). ArQule represents
that, upon payment of the foregoing amount, there are no amounts outstanding or
due from Pharmacia as of the date hereof under the Prior Agreement of which
ArQule is aware or should have been aware.

         3. Survival of Provisions. Notwithstanding the foregoing or anything to
the contrary in Section 11.4 of the Prior Agreement, the following provisions of
the Prior Agreement shall survive termination: Articles 8, 10, and 12 (except
for Section 12.15 which shall not survive).

         IN WITNESS WHEREOF, the undersigned have duly executed and delivered
this Agreement as a sealed instrument effective as of the date first above
written.



                                                                   EXHIBIT 10.31

PHARMACIA CORPORATION                         ARQULE, INC.
By: _________                          By: _____
         Name:                                Name:
         Title:                               Title: