# 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 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 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
          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 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:  May 16, 2005 |  | /s/William P. Hales
William P.  HalesPresident and Chief Executive Officer
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