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                                                                    EXHIBIT 31.1



CERTIFICATIONS

         I, Curtis W. Mewbourne, Chief Executive Officer of Mewbourne
Development Corporation, Managing General Partner of Mewbourne Energy Partners
03-A, L.P. (the "Registrant"), certify that:

         1. I have reviewed this quarterly report on Form 10-Q of Mewbourne
Energy Partners, 03-A, L.P.

         2. Based on my knowledge, this quarterly 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
quarterly 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 quarterly 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 we have:

         a) designed such disclosure controls and procedures 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 quarterly report
         is being prepared;

         b. evaluated the effectiveness of the registrant's disclosure controls
         and procedures as of a date within 90 days prior to the filing date of
         this quarterly report (the "Evaluation Date"); and

         c. presented in this quarterly report our conclusions about the
         effectiveness of the disclosure controls and procedures based on our
         evaluation as of the Evaluation Date;

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

         a. all significant deficiencies in the design or operation of internal
         controls which could adversely affect the registrant's ability to
         record, process, summarize and report financial data and have
         identified for the registrant's auditors any material weaknesses in
         internal controls; and


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         b. any fraud, whether or not material, that involves management or
         other employees who have a significant role in the registrant's
         internal controls; and

         6. The registrant's other certifying officers and I have indicated in
this quarterly report whether or not there were significant changes in internal
controls or in other factors that could significantly affect internal controls
subsequent to the date of our most recent evaluation, including any corrective
actions with regard to significant deficiencies and material weaknesses.

Date:   August 13, 2003.

                                       /s/   Curtis W. Mewbourne
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                                 Curtis W. Mewbourne
                                 Chief Executive Officer
                                 Mewbourne Development Corporation,
                                 Managing General Partner of the Registrant