**Exhibit 7.1(1 of 2)**

**PETROLEOS MEXICANOS, SUBSIDIARY ENTITIES ANDSUBSIDIARY COMPANIES**

**Computation of ratio of earnings      to fixed charges**(thousands of constant pesos asof December 31, 2003 )

   

|                                                              |                |   |                |   |                |   |
|-------------------------------------------------------------------|----------------|--------|----------------|--------|----------------|--------|
|                                                              | **2003**       |   | **2002**       |   | **2001**       |   |
| **Mexican GAAP**                                                  |           |   |           |   |           |   |
| Fixed charges (1):                                                |           |   |           |   |           |   |
|                                                              |           |   |           |   |           |   |
| Interest capitalized in fixed assets                              | 7,246,308      |   | 5,468,205      |   | 4,153,855      |   |
| Interest in the specific reserve for exploration    and depletion | 19,039         |   | 50,045         |   | 95,125         |   |
| Interest expense                                                  | 23,487,142     |   | 20,971,411     |   | 17,784,090     |   |
|                                                              |                |   |                |   |                |   |
|                                                              |           |   |           |   |           |   |
| Total interest cost                                               | 30,752,489     |   | 26,489,661     |   | 22,033,070     |   |
|                                                              |           |   |           |   |           |   |
| Total Fixed Charges                                               | 30,752,489     |   | 26,489,661     |   | 22,033,070     |   |
|                                                              |                |   |                |   |                |   |
|                                                              |           |   |           |   |           |   |
| Earnings after IEPS taxes and Hydrocarbon                         |           |   |           |   |           |   |
| Extraction duties                                                 | (40,644,363)   |   | (24,574,040)   |   | (30,395,660)   |   |
|                                                              |           |   |           |   |           |   |
| Fixed Charges (1):                                                |           |   |           |   |           |   |
| Interest cost net of amounts capitalized                          | 23,487,142     |   | 20,971,411     |   | 17,784,090     |   |
|                                                              |           |   |           |   |           |   |
|                                                              |           |   |           |   |           |   |
| Total Fixed Charges                                               | 23,487,142     |   | 20,971,411     |   | 17,784,090     |   |
|                                                              |                |   |                |   |                |   |
|                                                              |           |   |           |   |           |   |
| Earnings after taxes and duties plus fixed charges                |           |   |           |   |           |   |
| ( net of amounts capitalized )                                    | (17,157,221)   |   | (3,602,629)    |   | (12,611,570)   |   |
|                                                              |                |   |                |   |                |   |
|                                                              |           |   |           |   |           |   |
|                                                              |           |   |           |   |           |   |
| **Amount by which fixed charges exceed earnings**                 | **47,909,710** |   | **30,092,290** |   | **34,644,640** |   |
|                                                              |           |   |           |   |           |   |
|                                                              |           |   |           |   |           |   |
| (1) These figures do not include rental expense                   |           |   |           |   |           |   |

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**Exhibit 7.1(2 of 2)**

**PETROLEOS MEXICANOS, SUBSIDIARY ENTITIES ANDSUBSIDIARY COMPANIES**

**Computation of ratio of earnings      to fixed charges**( thousands of constant pesos      as of December 31, 2003 )

|                                                                |                |   |                |   |                |   |
|---------------------------------------------------------------------|----------------|--------|----------------|--------|----------------|--------|
|                                                                | **2003**       |   | **2002**       |   | **2001**       |   |
|                                                                |           |   |           |   |           |   |
| **U.S. GAAP**                                                       |           |   |           |   |           |   |
|                                                                |           |   |           |   |           |   |
| Fixed Charges (1):                                                  |           |   |           |   |           |   |
|                                                                |           |   |           |   |           |   |
|    Interest capitalized in fixed assets              | 7,954,598      |   | 6,000,176      |   | 5,713,858      |   |
|    Interest expense                                  | 22,797,891     |   | 20,489,485     |   | 16,319,212     |   |
|                                                                |                |   |                |   |                |   |
|                                                                |           |   |           |   |           |   |
| Total interest cost                                                 | 30,752,489     |   | 26,489,661     |   | 22,033,070     |   |
|                                                                |           |   |           |   |           |   |
|                                                                |           |   |           |   |           |   |
| Total Fixed Charges                                                 | 30,752,489     |   | 26,489,661     |   | 22,033,070     |   |
|                                                                |                |   |                |   |                |   |
|                                                                |           |   |           |   |           |   |
| Income Earnings after taxes and duties                              | (66,309,390)   |   | (32,666,715)   |   | (23,344,362)   |   |
|                                                                |           |   |           |   |           |   |
| Fixed Charges (1):                                                  |           |   |           |   |           |   |
| Interest cost net of amounts Capitalized                            | 22,797,891     |   | 20,489,485     |   | 16,319,212     |   |
|                                                                |           |   |           |   |           |   |
|                                                                |           |   |           |   |           |   |
| Total Fixed Charges (Net of amounts capitalized)                    | 22,797,891     |   | 20,489,485     |   | 16,319,212     |   |
|                                                                |                |   |                |   |                |   |
|                                                                |           |   |           |   |           |   |
| Earnings after taxes and duties plus fixed charges                  |           |   |           |   |           |   |
| (net of amounts capitalized)                                        | (43,511,499)   |   | (12,177,230)   |   | (7,025,150)    |   |
|                                                                |                |   |                |   |                |   |
|                                                                |           |   |           |   |           |   |
|                                                                |           |   |           |   |           |   |
|    **Amount by which fixed charges exceed earnings** | **74,263,988** |   | **38,666,891** |   | **29,058,220** |   |
|                                                                |           |   |           |   |           |   |
|                                                                |           |   |           |   |           |   |
| (1) These figures do not include rental expense                     |           |   |           |   |           |   |

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