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                                                                    EXHIBIT 12.1

                                  CERTIFICATION
                             PURSUANT TO SECTION 302

      I, Rick Yan, certify that:

      1. I have reviewed this annual report on Form 20-F of 51job, Inc.;

      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 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 and maintaining disclosure controls and procedures (as defined in
Exchange Act Rules 13a-15(e) and 15d-15(e)) 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 in which this report is being
      prepared;

            (b) [omitted pursuant to the guidance of Release No. 33-8238 (June
      5, 2003), Release No. 33-8392 (February 2, 2004) and Release No. 33-8545
      (March 2, 2005)];

            (c) Evaluated the effectiveness of the company's disclosure controls
      and procedures and presented in this report our conclusions about the
      effectiveness of the disclosure controls and procedures, as of the end of
      the period covered by this report based on such evaluation; and

            (d) Disclosed in this report any change in the company'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 company's internal control over financial
      reporting; and

      5. The company's other certifying officer(s) 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 the company's board of
directors (or persons performing the equivalent function):

            (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 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
      control over financial reporting.

Date:  June 29, 2006

By:    /s/ Rick Yan
       -------------------------------------
Name:  Rick Yan
Title: President and Chief Executive Officer