Exhibit 12.1**CERTIFICATION UNDER SECTION 302 OF THE SARBANES-OXLEY ACT**I, Chia Song Hwee, certify that:1. I have reviewed this annual report on Form 20-F, as amended by this Form 20-F/A, of CharteredSemiconductor Manufacturing Ltd.; 2. Based on my knowledge, this annual report does not contain any untrue statement of a materialfact or omit to state a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading with respect to the periodcovered by this report; 3. Based on my knowledge, the financial statements, and other financial information included inthis report, fairly present in all material respects the financial condition, results ofoperations and cash flows of the company as of, and for, the periods presented in this report; 4. The company’s other certifying officer(s) and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules13a-15(f) and 15d-15(f)) for the company and have: a) Designed such disclosure controls and procedures, or caused such disclosurecontrols and procedures to be designed under our supervision, to ensure that materialinformation relating to the company, including its consolidated subsidiaries, is madeknown to us by others within those entities, particularly during the period in whichthis report is being prepared;  b) Designed such internal control over financial reporting, or caused suchinternal control over financial reporting to be designed under our supervision, toprovide reasonable assistance regarding the reliability of financial reporting and thepreparation of financial statements for external purposes in accordance with generallyaccepted accounting principles;  c) Evaluated the effectiveness of the company’s disclosure controls and proceduresand presented in this report our conclusions about the effectiveness of the disclosurecontrols and procedures, as of the end of the period covered by this report based onsuch evaluation;  d) Disclosed in this report any change in the company’s internal control overfinancial reporting that occurred during the period covered by the annual report thathas materially affected, or is reasonably likely to materially affect, the company’sinternal control over financial reporting; and5. The company’s other certifying officer(s) and I have disclosed, based on our most recentevaluation of the internal control over financial reporting, to the company’s auditors and theaudit committee of the company’s board of directors (or persons performing the equivalentfunctions): a) All significant deficiencies and material weaknesses in the design or operationof internal control over financial reporting which are reasonably likely to adverselyaffect the company’s ability to record, process, summarize and report financialinformation; and  b) Any fraud, whether or not material, that involves management or other employeeswho have a significant role in the company’s internal control over financial reporting.Date:June 29, 2007                                          /s/ Chia Song Hwee   Chia Song Hwee   President and Chief Executive Officer