Exhibit 12.1

                               INFICON Holding AG
                 Sarbanes-Oxley Act Section 302(a) Certification

I, Lukas Winkler, certify that:

      1.    I have reviewed this Annual Report on Form 20-F of INFICON Holding
            AG;

      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 registrant as of, and for, the periods presented in
            this report;

      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:

            a)    designed such disclosure controls and procedures 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 annual report is being prepared;

            b)    designed such internal control over financial reporting, or
                  caused such internal control over financial reporting to be
                  designed under our supervision to provide reasonable assurance
                  regarding the reliability of financial reporting and the
                  preparation of financial statements for external purposes in
                  accordance with generally accepted accounting principles

            c)    evaluated the effectiveness of the registrant's disclosure
                  controls and procedures as of a date within 90 days prior to
                  the filing date of this annual report (the "Evaluation Date");
                  and

            d)    disclosed in this report any change in the registrant's
                  internal control over financial reporting that occurred during
                  the period covered by the annual report that has materially
                  affected, or is reasonably likely to materially affect, the
                  registrant's internal control over financial reporting;

      5.    The registrant's other certifying officer and I have disclosed,
            based on our most recent evaluation, to the registrant's auditors
            and the audit committee of the registrant's board of directors:

            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

            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.

Date: March 1, 2004


/s/ Lukas Winkler

Lukas Winkler
Chief Executive Officer and President


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