Exhibit 12.1
  CERTIFICATION
    1.
    I have reviewed this amendment to the annual report on
    Form 20-F/A
    of Petróleos Mexicanos;  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 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))
    and internal control over financial reporting (as defined in
    Exchange Act
    Rules 13a-15(f)
    and
    15d-15(f))
    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)
    Designed such internal control over financial reporting, or
    caused such internal control over financial reporting to be
    designed under our supervision, to provide reasonable assurance
    regarding the reliability of financial reporting and the
    preparation of financial statements for external purposes in
    accordance with generally accepted accounting principles;  (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 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.    
   Title:
    Director General/Chief Executive Officer