


                                                                    Exhibit 23.1

                       CONSENT OF INDEPENDENT AUDITORS 

    We consent to the reference to our firm under the captions "Experts" and 
"Selected Consolidated Financial Data" and to the use of our report dated May 
6, 1996 (except for Note 10 as to which the date is July 10, 1996 and Note 11 
as to which the date is November 19, 1996), in the Registration Statement 
(Form S-1) and the related Prospectus of Pegasystems Inc. for the 
registration of 2,581,750 shares of its common stock. 

   Our audits also included the financial statement schedule of Pegasystems 
Inc. located at Exhibit 99.1. This schedule is the responsibility of the 
Company's management. Our responsibility is to express an opinion based on 
our audits. In our opinion, the financial statement schedule referred to 
above, when considered in relation to the basic financial statements taken as 
a whole, presents fairly in all material respects the information set forth 
therein. 

ERNST & YOUNG LLP 
Boston, Massachusetts 
November 19, 1996 

