**Exhibit 12.1****CERTIFICATION OF CHIEF EXECUTIVE OFFICER PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002**I, Klaus Kleinfeld, certify that:1. I have reviewed this annual report on Form 20-F of Siemens Aktiengesellschaft; 2. Based on my knowledge, this report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make thestatements made, in light of the circumstances under which such statementswere made, not misleading with respect to the period covered by this report; 3. Based on my knowledge, the financial statements, and other financialinformation included in this report, fairly present in all material respectsthe financial condition, results of operations and cash flows of the companyas of, and for, the periods presented in this report; 4. The company’s other certifying officer(s) and I are responsible forestablishing and maintaining disclosure controls and procedures (as definedin Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control overfinancial reporting (as defined in Exchange Act Rules 13a-15(f) and15d-15(f)) for the company and have: (a) Designed such disclosure controls and procedures, or caused suchdisclosure controls and procedures to be designed under oursupervision, to ensure that material information relating to thecompany, including its consolidated subsidiaries, is made known to usby others within those entities, particularly during the period inwhich this report is being prepared;  (b) Designed such internal control over financial reporting, or causedsuch internal control over financial reporting to be designed underour supervision, to provide reasonable assurance regarding thereliability of financial reporting and the preparation of financialstatements for external purposes in accordance with generally acceptedaccounting principles;  (c) Evaluated the effectiveness of the company’s disclosure controls andprocedures and presented in this report our conclusions about theeffectiveness of the disclosure controls and procedures, as of the endof the period covered by this report based on such evaluation; and  (d) Disclosed in this report any change in the company’s internal controlover financial reporting that occurred during the period covered bythe annual report that has materially affected, or is reasonablylikely to materially affect, the company’s internal control overfinancial reporting; and5. The company’s other certifying officer(s) and I have disclosed, basedon our most recent evaluation of internal control over financialreporting, to the company’s auditors and the audit committee of thecompany’s board of directors (or persons performing the equivalentfunctions): (a) All significant deficiencies and material weaknesses in the design oroperation of internal control over financial reporting which arereasonably 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 otheremployees who have a significant role in the company’s internalcontrol over financial reporting.Date: December 11, 2006                   /s/ KLAUS KLEINFELD   Klaus Kleinfeld   Chief Executive Officer