Exhibit 31.1

Certification of
Principal Executive Officer Pursuant to Rule 13a-14(a)
ofSecurities Exchange Act
of 1934

I, William P. Hales, the principal
executive officer of Hemagen Diagnostics Inc, certify that:

| | 1. | I have reviewed this quarterly report on Form 10-QSB of Hemagen Diagnostics,
               Inc;
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| | 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;
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| | 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;
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| | 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 we have:
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| | 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;
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| | b. | 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
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| | c. | 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 that has materially affected, or is reasonably likely to
          materially affect, the registrants internal control over financial
          reporting; and
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| | 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):
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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
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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 control over
          financial reporting; and
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|Date:  May 16, 2004 |  | BY: /s/William Hales
William HalesPresident and Chief Executive Officer
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