

                                                                       Item 1.6

                                 PROMISSORY NOTE


$165,000.00
- -----------
                                                           Boston, Massachusetts
                                                           December 28, 1995
                                                           ------------

         FOR VALUE RECEIVED, the undersigned Pegasystems Inc., a Massachusetts
corporation (the "Borrower") hereby promises to pay to the order of FLEET BANK
OF MASSACHUSETTS, N.A. (the "Bank") the principal amount of One Hundred Sixty
Five Thousand and 00/100 ($165,000.00) Dollars ("Principal"), with interest, at
the rate hereinafter set forth, on the daily balance of all unpaid Principal,
from the date hereof until payment in full of all Principal and interest
hereunder. As used herein, "Letter Agreement" means that certain letter
agreement dated December 16, 1993 between the Borrower and the Bank, as amended.

         Interest on all unpaid Principal shall be due and payable monthly in
arrears, on the first day of each month commencing on the first such date after
the date hereof and continuing on the first day of each month thereafter and on
the date of payment of this note in full, at fluctuating rate per annum
(computed on the basis of a year of three hundred sixty (360) days for the
actual number of days elapsed) which shall at all times be equal to the sum of
(i) one-half of one (0.5%) percent per annum plus (ii) the Prime Rate, as in
effect from time to time (but in no event in excess of the maximum rate
permitted by then applicable law). A change in the aforesaid rate of interest
will become effective on the same day on which any change in the Prime Rate is
effective. Overdue Principal and, to the extent permitted by law, overdue
interest shall bear interest at a fluctuating rate per annum which at all times
shall be equal to the sum of (i) two (2%) percent per annum plus (ii) the per
annum rate otherwise payable under this note (but in no event in excess of the
maximum rate permitted by then applicable law), compounded monthly and payable
on demand. As used herein, "Prime Rate" means that rate of interest per annum
announced by the Bank from time to time as its prime rate, it being understood
that such rate is merely a reference rate, not necessarily the lowest, which
serves as the basis upon which effective rates of interest are calculated for
obligations making reference thereto. If the entire amount of any required
Principal and/or interest is not paid within ten (10) days after the same is
due, the Borrower shall pay to the Bank a late fee equal to five percent (5%) of
the required payment, provided that such late fee shall be reduced to three
percent (3%) of any required principal and interest that is not paid within
fifteen (15) days of the date it is due if this note is secured by a mortgage on
an owner-occupied residence of 1-4 units.

         Principal shall be repaid in thirty-five (35) equal consecutive monthly
installments (each in an amount equal to


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$4,583.33) commencing on [first day of month following date of note] and
continuing on the first day of each month thereafter through and including
[first day of 35th month following month in which note is executed] plus a
thirty-sixty (36th) and final payment due on [first day of 36th month following
month in which note is executed] in an amount equal to all then remaining
Principal and all interest accrued but unpaid thereon. The Borrower may at any
time and from time to time, without premium or penalty, prepay all or any
portion of said Principal, each such prepayment to be applied against Principal
installments in inverse order of normal maturity.

         Payments of both Principal and interest shall be made, in immediately
available funds, at the principal office of the Bank (now located at 75 State
Street, Boston, Massachusetts 02109), or at such other address as the Bank may
from time to time designate.

         The undersigned Borrower irrevocably authorizes the Bank to make or
cause to be made, on a schedule attached to this note or on the books of the
Bank, at or following the time of making the Facility Two Term Loan (as defined
in the Letter Agreement) evidenced by this note and of receiving any payment of
Principal, an appropriate notation reflecting such transaction and the then
aggregate unpaid balance of Principal. Failure of the Bank to make any such
notation shall not, however, affect any obligation of the Borrower hereunder or
under the Letter Agreement. The aggregate unpaid principal amount of the
Facility Two Term Loan evidenced by this note, as recorded by the Bank from time
to time on such schedule or on such books, shall constitute prima facie evidence
of such amount.

         The Borrower hereby (a) waives notice of and consents to any and all
advances, settlements, compromises, favors and indulgences (including, without
limitation, any extension or postponement of the time for payment), any and all
receipts, substitutions, additions, exchanges and releases of collateral, and
any and all additions, substitutions and releases of any person primarily or
secondarily liable, (b) waives presentment, demand, notice, protest and all
other demands and notices generally in connection with the delivery, acceptance,
performance, default or enforcement of or under this note, and (c) agrees to pay
all costs and expenses, including, without limitation, reasonable attorneys'
fees, incurred or paid by the Bank in enforcing this note and any collateral or
security therefor, all whether or not litigation is commenced.

         This note is one of the Facility Two Term Notes referred to in the
Letter Agreement. This note is secured by, and is entitled to the benefits of,
the Security Agreement (as defined in the Letter Agreement). This note is
subject to prepayment as set forth in the Letter Agreement. The maturity of this
note may

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be accelerated upon the occurrence of an Event of Default, as
provided in the Letter Agreement.

         Executed, as an instrument under seal, as of the day and year first
above written.


CORPORATE 
 SEAL
ATTEST:


                                                 PEGASYSTEMS, INC.



- ---------------------------                      By: [Signature of Ira Vishner]
Clerk                                                --------------------------
                                                     Its Treasurer



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