Exhibit 31.1

                                  CERTIFICATION

I, Dennis R. Neill, certify that:

1.    I have reviewed  this Annual Report on Form 10-K of Geodyne  Energy Income
      Limited Partnership III-A;

2.    Based on my  knowledge,  this  annual  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 annual 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(s) 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;

      (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(s) 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):



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      (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: April 16, 2007


                                    //S//Dennis R. Neill
                                    ----------------------------
                                    Dennis R. Neill, President
                                    (Principal Executive Officer)






































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