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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 is made
                  known to us 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 the 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



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                  financial data and have identified for the registrant's
                  auditors any material weaknesses in internal controls; and

                  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:   November 13, 2003.

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