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                                                                    EXHIBIT 31.1

                                 CERTIFICATIONS

             CERTIFICATION PURSUANT TO RULE 13a-14(a) AND 15d-14(a)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

I, Luis Marin, President and Chief Executive Officer of CITGO Petroleum
Corporation (the "registrant"), certify that:

1.       I have reviewed this quarterly report on Form 10-Q for the quarter
         ended June 30, 2003 of the registrant;

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 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) 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;

         c) 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 that has materially affected, or is
         reasonably likely to materially affect, the registrant's internal
         control over financial reporting; and

5.       The registrant's other certifying officer 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
         function):

         a) All significant deficiencies and material weaknesses in the design
         or operation of internal control 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:   August 18, 2003                /s/     Luis Marin
               --------------------             -------------------------------
                                                Name:   Luis Marin
                                                Title:  Chief Executive Officer