EXHIBIT 31.1

                                 CERTIFICATIONS

I, John R. Irwin, certify that:

1.    I have reviewed this annual report on Form 10-K of Atwood
      Oceanics, 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 registrant as of, and for,
      the periods presented in this report;

4.    The registrant'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 registrant 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 registrant, 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) [Paragraph omitted in accordance with SEC transition
      instructions contained in SEC Releases 34-47986 and 34-49313];
      and

      (c) Evaluated the effectiveness of the registrant'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 registrant's
      internal control over financial reporting that occurred during
      the registrant's most recent fiscal quarter (the registrant's
      fourth fiscal quarter in the case of an annual report) that
      has materially affected, or is reasonably likely to materially
      affect, the registrant's internal control over financial
      reporting; and

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5.    The registrant's other certifying officer(s) and I have
      disclosed, based on our most recent evaluation of internal
      control over financial reporting, to the registrant's auditors
      and the audit committee of the registrant's board of directors
      (or persons performing the equivalent functions):

      (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
      registrant'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 registrant's
      internal control over financial reporting.

Date: December 10, 2004

                  /s/ John R. Irwin
                  John R. Irwin
                  Chief Executive Officer


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