Exhibit 12.1
**CERTIFICATION**
     I, Shin Bae Kim, certify that:
     1.     I have reviewed this annual report on Form 20-F of SK Telecom Co., Ltd. (“SK Telecom”);
     2.     Based on my knowledge, this annual report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make the statements made, in light ofthe circumstances under which such statements were made, not misleading with respect to the periodcovered by this annual report;
     3.     Based on my knowledge, the financial statements, and other financial information includedin this annual report, fairly present in all material respects the financial condition, results ofoperations and cash flows of SK Telecom as of, and for, the periods presented in this annualreport;
     4.     SK Telecom’s other certifying officer(s) and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) underthe U.S. Securities Exchange Act of 1934, as amended) for SK Telecom and have:
          (a)     designed such disclosure controls and procedures to ensure that material informationrelating to SK Telecom, including its consolidated subsidiaries, is made known to us by otherswithin those entities, particularly during the period in which this annual report is beingprepared;
          (b)     evaluated the effectiveness of SK Telecom’s disclosure controls and procedures andpresented in this annual report our conclusions about the effectiveness of the disclosure controlsand procedures, as of the end of the period covered by this annual report based on such evaluation;and
          (c)     disclosed in this annual report any change in SK Telecom’s internal control over financialreporting that occurred during the period covered by this annual report that has materiallyaffected, or is reasonably likely to materially affect, SK Telecom’s internal control overfinancial reporting;
     5.     SK Telecom’s other certifying officer(s) and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to SK Telecom’s auditors and the auditcommittee of SK Telecom’s board of directors (or persons performing the equivalent functions):
          (a)     all significant deficiencies and material weaknesses in the design or operation ofinternal control over financial reporting which are
 

 

reasonably likely to adversely affect SK Telecom’s ability to record, process, summarize and reportfinancial information; and
          (b)     any fraud, whether or not material, that involves management or other employees who have asignificant role in SK Telecom’s internal control over financial reporting; and
     6.     SK Telecom’s other certifying officer(s) and I have indicated in this annual report whetherthere were significant changes in internal controls or in other factors that could significantlyaffect internal controls subsequent to the date of our most recent evaluation, including anycorrective actions with regard to significant deficiencies and material weaknesses.
Date: May 31, 2005            /s/ Shin Bae Kim   Name:  Shin Bae Kim   Title:  Chief Executive Officer   
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