**Exhibit 12.1**

**CERTIFICATION**

               I, Juan José Suárez Coppel, certify that:

1.            I have reviewed this annual report on Form 20-F of PetróleosMexicanos; 

2.            Based on my knowledge, this report does not contain anyuntrue 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 otherfinancial 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 forestablishing 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 andhave: 

(a)        Designed such disclosure controls and procedures, or caused suchdisclosure 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 duringthe period in which this report is being prepared; 

(b)        Designed such internalcontrol 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 financialstatements for external purposes in accordance with generally accepted accounting principles; 

(c)        Evaluated the effectiveness of the company’s disclosure controls and proceduresand 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 overfinancial 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 ourmost 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 ofinternal 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 whohave a significant role in the company’s internal control over financial reporting. 

Date: April 30, 2012