Exhibit 12.1
 CERTIFICATION OF CHIEF EXECUTIVE OFFICER
  1.
    
    I have reviewed this annual report on Form 20-F of Infineon Technologies AG;2.
    
    Based on my knowledge, this annual 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 annual 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
annual report;4.
    
    The company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))
and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and
15d-15(f)) for the company 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 company, including its consolidated subsidiaries, is made
known to us by others within those entities, particularly during the period during
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 companys disclosure controls and procedures
and presented in this annual report our conclusions about the effectiveness of the
disclosure controls and procedures, as of the end of the period covered by this annual
report based on such evaluation; and(d)
    
    disclosed in this annual report any change in the companys internal control
over financial reporting that occurred during the period covered by this annual report
that has materially affected, or is reasonably likely to materially affect, the
companys internal control over financial reporting; and
 5.
    
    The companys other certifying officer and I have disclosed, based on our most recent
evaluation of internal control over financial reporting, to the companys auditors and the
audit committee of companys board of directors (or persons performing the equivalent
functions):
 (a)
    
    all significant deficiencies and material weaknesses in the design or operation
of internal controls over financial reporting which are reasonably likely to adversely
affect the company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 companys internal controls over financial
reporting.
  /s/ Peter BauerPeter BauerMember of the Management Board and

Chief Executive Officer