Exhibit 7.1

(
 1
 of 2)

PETROLEOS MEXICANOS, SUBSIDIARY ENTITIES AND SUBSIDIARY COMPANIES

Computation of ratio of earnings to fixed charges

(Thousand of constant pesos as of December 31, 2005)



|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|------------------------------------------------------------------------------- |  | ---- | ----------- | - | ---- | --- | ----------- | ---- |  | --- | ----------- | - |  | ---- | ----------- | - |  | --- | ----------- | -
|                                                                                |  | 2005 |             |   | 2004 |     |             | 2003 |  |     | 2002        |   |  | 2001 |            
|Mexican GAAP                                                                    |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|                                                                                |  |      |             |   |     
|Fixed Charges(1):                                                               |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Interest capitalized in fixed assets                                            |  | Ps.  | 5,132,219   |   |      | Ps. | 4,484,570   |      |  | Ps. | 7,876,482   |   |  | Ps.  | 5,943,752   |   |  | Ps. | 4,515,096   |  
|Interest in the specific reserve for exploration and depletion                  |  |      |             |   |      |     |             |      |  |     | 20,697      |   |  |      | 54,392      |   |  |     | 103,398     |  
|Interest expense                                                                |  |      | 52,930,496  |   |      |     | 32,823,197  |      |  |     | 25,529,698  |   |  |      | 22,795,188  |   |  |     | 19,330,691  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Total interest cost                                                             |  |      | 58,062,715  |   |      |     | 37,307,767  |      |  |     | 33,426,877  |   |  |      | 28,793,332  |   |  |     | 23,949,185  |  
|Total Fixed Charges                                                             |  |      | 58,062,715  |   |      |     | 37,307,767  |      |  |     | 33,426,877  |   |  |      | 28,793,332  |   |  |     | 23,949,185  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|                                                                                |  |      |             |   |     
|Earnings after IEPS taxes and Hydrocarbon Extraction duties                     |  |      | (76,282,350 | ) |      |     | (26,345,302 | )    |  |     | (44,178,998 | ) |  |      | (26,711,132 | ) |  |     | (33,039,032 | )
|                                                                                |  |      |             |   |     
|Fixed Charges(1):                                                               |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Interest cost (net of amounts capitalized)                                      |  |      | 52,930,496  |   |      |     | 32,823,197  |      |  |     | 25,529,698  |   |  |      | 22,795,188  |   |  |     | 19,330,691  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Total Fixed Charges (net of amounts capitalized)                                |  |      | 52,930,496  |   |      |     | 32,823,197  |      |  |     | 25,529,698  |   |  |      | 22,795,188  |   |  |     | 19,330,691  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Earnings after taxes and duties plus fixed charges (net of amounts capitalized) |  |      | (23,351,854 | ) |      |     | 6,477,895   |      |  |     | (18,649,300 | ) |  |      | (3,915,944  | ) |  |     | (13,708,341 | )
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Amount by which fixed charges exceed earnings                                   |  | Ps.  | 81,414,569  |   |      | Ps. | 30,829,872  |      |  | Ps. | 52,076,177  |   |  | Ps.  | 32,709,276  |   |  | Ps. | 37,657,526  |  

---

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



---

Exhibit 7.1

(
 2
 of 2)



PETROLEOS
MEXICANOS SUBSIDIARY ENTITIES AND SUBSIDIARY COMPANIES

Computation of ratio of earnings to fixed charges

(Thousand of constant pesos as of December 31, 2005)



|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|------------------------------------------------------------------------------- |  | ---- | ----------- | - | ---- | --- | ----------- | ---- |  | --- | ----------- | - |  | ---- | ----------- | - |  | --- | ----------- | -
|                                                                                |  | 2005 |             |   | 2004 |     |             | 2003 |  |     | 2002        |   |  | 2001 |            
|U.S. GAAP                                                                       |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|                                                                                |  |      |             |   |     
|Fixed Charges(1):                                                               |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Interest capitalized in fixed assets                                            |  | Ps.  | 5,855,586   |   |      | Ps. | 5,402,477   |      |  | Ps. | 8,646,369   |   |  | Ps.  | 6,521,981   |   |  | Ps. | 6,210,766   |  
|Interest expense                                                                |  |      | 52,207,129  |   |      |     | 31,905,290  |      |  |     | 24,780,508  |   |  |      | 22,271,352  |   |  |     | 17,738,420  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Total interest cost                                                             |  |      | 58,062,715  |   |      |     | 37,307,767  |      |  |     | 33,426,877  |   |  |      | 28,793,333  |   |  |     | 23,949,186  |  
|Total Fixed Charges                                                             |  |      | 58,062,715  |   |      |     | 37,307,767  |      |  |     | 33,426,877  |   |  |      | 28,793,333  |   |  |     | 23,949,186  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|                                                                                |  |      |             |   |     
|Income Earnings after taxes and duties                                          |  |      | (73,904,438 | ) |      |     | (13,444,806 | )    |  |     | (72,075,981 | ) |  |      | (35,507,556 | ) |  |     | (25,374,514 | )
|                                                                                |  |      |             |   |     
|Fixed Charges(1):                                                               |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Interest cost (net of amounts capitalized)                                      |  |      | 52,207,129  |   |      |     | 31,905,290  |      |  |     | 24,780,508  |   |  |      | 22,271,352  |   |  |     | 17,738,420  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Total Fixed Charges (net of amounts capitalized)                                |  |      | 52,207,129  |   |      |     | 31,905,290  |      |  |     | 24,780,508  |   |  |      | 22,271,352  |   |  |     | 17,738,420  |  
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Earnings after taxes and duties plus fixed charges (net of amounts capitalized) |  |      | (21,697,309 | ) |      |     | 18,460,484  |      |  |     | (47,295,473 | ) |  |      | (13,236,204 | ) |  |     | (7,636,094  | )
|                                                                                |  |      |             |   |      |     |             |      |  |     |             |   |  |      |             |   |  |     |             |  
|Amount by which fixed charges exceed earnings                                   |  | Ps.  | 76,760,024  |   |      | Ps. | 18,847,283  |      |  | Ps. | 80,722,350  |   |  | Ps.  | 42,029,537  |   |  | Ps. | 31,585,280  |  

---

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