Exhibit 31.1
                               Certifications

         I, Gerald A. Potthoff, certify that:


1.   I have reviewed this annual report on Form 10-K of Engineered Support
     Systems, Inc.

2.   Based on my knowledge, this annual report does not contain any untrue
     statements of a material fact or omit to state a material fact
     necessary to make the statements made, in light of the circumstances
     under which such statements were made, not misleading with respect to
     the period covered by this report;

3.   Based on my knowledge, the financial statements, and other financial
     information included in this report, fairly present in all material
     respects the financial condition, results of operations and cash flows
     of the registrant as of, and for, the periods presented in this annual
     report.

4.   The registrant's other certifying officers and I are responsible for
     establishing and maintaining disclosure controls and procedures (as
     defined in Exchange Act Rules 13a-14 and 15d-14) for the registrant and
     have:

         a)   Designed such disclosure controls and procedures, or caused
              such disclosure controls and procedures to be designed under
              our supervision, to ensure that material information relating
              to the registrant, including its consolidated subsidiaries, is
              made known to us by others within those entities, particularly
              during the period in which this annual report is being
              prepared;

         b)   Evaluated the effectiveness of the registrant's disclosure
              controls and procedures and presented in this report our
              conclusions about the effectiveness of the disclosure controls
              and procedures, as of the end of the period covered by this
              report based on such evaluation; and

         c)   Disclosed in the report, any change in the registrant's
              internal control over financial reporting that occurred during
              the registrant's most recent fiscal quarter that has
              materially affected, or is reasonably likely to materially
              affect, the registrant's internal control over financial
              reporting.

5.   The registrant's other certifying officers and I have disclosed, based
     on our most recent evaluation of internal control over financial
     reporting, to the registrant's auditors and the audit committee of the
     registrant's board of directors (or persons performing the equivalent
     functions):

         a)   All significant deficiencies and material weaknesses in the
              design or operation of internal control over financial
              reporting which are reasonably likely to adversely affect the
              registrant's ability to record, process, summarize and report
              financial information; and

         b)   Any fraud, whether or not material, that involves management
              or other employees who have a significant role in the
              registrant's internal control over financial reporting.

Date: February 1, 2005

                                       /s/ Gerald A. Potthoff
                                       ----------------------------------------
                                       Gerald A. Potthoff
                                       Vice Chairman, Chief Executive Officer
                                       and President