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                                                                    Exhibit 31.1
                                  CERTIFICATION
                                  -------------

I, Paulita M. LaPlante, certify that:

     1.   I have reviewed this annual report on Form 10-KSB of Optical Sensors
          Incorporated;

     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;

     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;

     4.   The small business issuer'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 small business issuer 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
               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;

               (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

               (c) Disclosed in this report any change in the small business
               issuer's internal control over financial reporting (as defined in
               Exchange Act Rules 13a-15(f) and 15d-15(f)) 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

     5.   The small business issuer's other certifying officer(s) 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):

               (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

               (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.

Date:  April 9, 2004


                                        By:    /s/ Paulita M. LaPlante
                                               ---------------------------------
                                        Title: President and Chief Executive
                                               Officer