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                                                                    Exhibit 31.1

                                  CERTIFICATION

I, Nathan Zommer, certify that:

1.      I have reviewed this annual report on Form 10-K of IXYS Corporation;

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 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 officers 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;

        (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 evaluations; and

        (c)     Disclosed in this report any change in the registrant's interest
                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 registrant's board of
directors (or persons performing the equivalent function):

        (a)     All significant deficiencies 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 controls over financial reporting.


Date: June 14, 2004



                                 /s/ Nathan Zommer
                                 -----------------------------------------------
                                 Nathan Zommer
                                 President, Chief Executive Officer and Chairman
                                 (Principal Executive Officer)