# Exhibit 31.1

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

I, William P. Hales certify that:

|1. | I have reviewed this quarterly report on Form 10-QSB/A 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 small business issuer as
               of, and for, the periods presented in this report;
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|4. | The small business issuer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 small business issuer and
               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 small business issuer, 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 small business issuer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 small business issuers internal
               control over financial reporting that occurred during the small business
               issuers most recent fiscal quarter (the small business issuers
               fourth fiscal quarter in the case of an annual report) that has materially
               affected, or is reasonably likely to materially affect, the small business
               issuers internal control over financial reporting; and
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|5. | The small business issuers other certifying officer and I have disclosed,
               based on our most recent evaluation of internal control over financial
               reporting, to the small business issuers auditors and the audit committee
               of the small business issuer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 small business issuer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 small business issuers internal control
               over financial reporting.
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Date:    August 16, 2005

| |  | BY: /s/William P. Hales
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      William P. Hales
      President and Chief Executive Officer
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