Exhibit 7.1

PETROLEOS MEXICANOS SUBSIDIARY ENTITIES AND SUBSIDIARY COMPANIES

Computation of ratio of earnings to fixed charges

(In thousands of Mexican pesos)



|                                                                             |  |      |             |   |      |  |              |  
|---------------------------------------------------------------------------- |  | ---- | ----------- | - | ---- |  | ------------ | -
|                                                                             |  | 2012 |             |   | 2011 | 
|IFRS                                                                         |  |      |             |   |      |  |              |  
|Fixed Charges(1):                                                            |  |      |             |   |      |  |              |  
|Interest capitalized in fixed assets                                         |  |      | 2,110,075   |   |      |  | 4,292,351    |  
|Interest expense                                                             |  |      | 72,951,202  |   |      |  | 63,003,854   |  
|                                                                             |  |      |             |   |      |  |              |  
|Total interest cost                                                          |  |      | 75,061,277  |   |      |  | 67,296,206   |  
|Total Fixed Charges                                                          |  |      | 75,061,277  |   |      |  | 67,296,206   |  
|                                                                             |  |      |             |   |      |  |              |  
|Net income (loss)                                                            |  |      | 2,600,478   |   |      |  | (106,942,257 | )
|Hydrocarbon Income Tax (IRP)                                                 |  |      | 2,442,280   |   |      |  | (677,392     | )
|Income Tax and Others                                                        |  |      | 2,138,856   |   |      |  | 3,853,408    |  
|Profit sharing in subsidiaries and affiliates (income from equity investees) |  |      | 4,797,607   |   |      |  | (810,753     | )
|                                                                             |  |      |             |   |      |  |              |  
|Pretax income from continuing operations before income from equity investees |  |      | 11,979,221  |   |      |  | (104,576,993 | )
|Fixed Charges(1):                                                            |  |      | 75,061,277  |   |      |  | 67,296,206   |  
|Amortization of interest capitalized                                         |  |      | 84,403      |   |      |  | 171,694      |  
|Dividends received on Investments in shares                                  |  |      | 685,704     |   |      |  | 599,907      |  
|Interest capitalized in fixed assets                                         |  |      | (2,110,075  | ) |      |  | (4,292,351   | )
|                                                                             |  |      |             |   |      |  |              |  
|Earnings                                                                     |  |      | 85,700,530  |   |      |  | (40,801,538  | )
|                                                                             |  |      |             |   |      |  |              |  
|Amount by which fixed charges exceed earnings                                |  |      | (10,639,253 | ) |      |  | 108,097,743  |  
|Ratio of earnings to fixed charges                                           |  |      | 1.14        |   |      |  | (0.61        | )



|(1) | These figures do not include rental expense.
|--- | --------------------------------------------