EXHIBIT 31.1 

**CERTIFICATIONS**

           I, Curtis W. Mewbourne certifythat: 

1.        I have reviewed this quarterly report on Form 10-Q of Mewbourne Energy Partners03-A, L.P. 

2.        Based on my knowledge, this quarterly report does not contain any untruestatement 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 informationincluded 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 andmaintaining 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) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assuranceregarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles; 

(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 andprocedures, as of the end of the period covered by this report based on such evaluation; and 

(d) Disclosed in thisreport 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 hasmaterially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and 

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’sboard of directors (or persons performing the equivalent function): 

(a) all significant deficiencies in the design oroperation 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 

(b) any fraud, whether or not material, that involves management or other employees who have a significant role inthe registrant’s internal control over financial reporting. 

Date:                November 16, 2009