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                                                                Exhibit 31.1

CERTIFICATIONS
I, Gerald A. Potthoff, certify that:

         1.   I have reviewed this quarterly report on Form 10-Q of
              Engineered Support Systems, Inc.;

         2.   Based on my knowledge, this report does not contain any untrue
              statement 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 quarterly 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
              report;

         4.   The registrant's other certifying officer and I are
              responsible for establishing and maintaining disclosure
              controls and procedures (as defined in Exchange Act Rules
              13a-15(e) and 15d-15(e)) 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 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 this 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; and

         5.   The registrant's other certifying officer 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 weakness 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: June 9, 2005

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