<PAGE>
                                                                   Exhibit 31.1


                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER


I, Stratton J. Nicolaides, certify that:

1.       I have reviewed this amended annual report on Form 10-K/A of Numerex
Corp.;

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 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)       [omitted pursuant to the guidance of Release No. 33-8283
         (June 5, 2003)]

         c)       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

         d)       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 (the registrant's fourth
         fiscal quarter in the case of an annual report) 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 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: March 30, 2004


                                           /s/  Stratton J. Nicolaides
                                           ------------------------------------
                                           Stratton J. Nicolaides
                                           Chief Executive Officer and Chairman


                                      -3-