1 EXHIBIT 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS We consent to the incorporation by reference in this Registration Statement of American Management Systems, Incorporated on Form S-8 of our reports dated February 16, 2000, appearing in and incorporated by reference in the Annual Report on Form 10-K of American Management Systems, Incorporated for the year ended Decemebr 31, 1999. DELOITTE & TOUCHE LLP McLean, Virginia March 30, 2000 -9-