UNITED STATES
  SECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER 
  PURSUANT TO RULE 13a-16 OR 15d-16 UNDER 
  THE SECURITIES EXCHANGE ACT OF 1934

For the month of April, 2005 
  Commission File Number 0-99

PETROLEOS MEXICANOS




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(Exact name of registrant as specified in its charter)




MEXICAN PETROLEUM


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(Translation of registrants name into English)




United Mexican States


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(Jurisdiction of incorporation or organization)




Avenida Marina Nacional No. 329 
  Colonia Huasteca 
  Mexico, D.F. 11311
  Mexico

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(Address of principal executive offices)




Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F  X               Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1)

Yes     No   X

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7)

Yes     No   X

Indicate by check mark whether the registrant by furnishing the information contained in this form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes     No   X





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|                                             | April 13, 2005                                                                
|-------------------------------------------- | ------------------------------------------------------------------------------
|                                            
|Hydrocarbon reserves as of December 31, 2004
|                                            
|Disclaimer                                   | We would like to note that our comments during this conference call may       
|                                             | include forward looking statements. Listeners are cautioned not to place      
|                                             | undue reliance on any forward looking statements and to review the            
|                                             | cautionary notes that appear on last pages of our earnings report, published  
|                                             | on the Investor Relations section on PEMEXs website.                         
|                                            
|Cautionary                                   | We would also like to note that the United States Securities and Exchange     
|note                                         | Commission (SEC) permits oil and gas companies, in their filings with the     
|                                             | SEC, to disclose only proved reserves that a company has demonstrated by      
|                                             | actual production or conclusive formation tests to be economically and legally
|                                             | producible under existing economic and operating conditions. We use certain   
|                                             | terms in this conference call such as total reserves, probable reserves,      
|                                             | possible reserves, 3P and 2P reserves, that the SEC's guidelines strictly     
|                                             | prohibit us from including in filings with the SEC. Investors are urged to    
|                                             | consider closely the disclosure in our Form 20-F, available also from us at   
|                                             | www.pemex.com.                                                                

---

|Presentation  |                                                                           
|------------- | --------------------------------------------------------------------------
|             
|Introduction  |                                                                           
|             
|Objective and | The objective is to present the main results of the reserves evaluation   
|content       | process as of December 31, 2004.                                          
|             
|              | •   Summary of some basic definitions                                     
|              | •   Results of the evaluation as of December 31 2004, its distribution and
|              | some relevant indicators                                                  
|              | •   Main discoveries                                                      
|              | •   Q&A session                                                           



|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Institutional |  | With the purpose of standardizing the estimation of reserves and                  
|------------- |  | ----------------------------------------------------------------------------------
|measuring     |  | classification processes, the measurement of hydrocarbon reserves at              
|system        |  | PEMEX is done, since 1996, based upon international definitions issued by         
|              |  | the Society of Petroleum Engineers (SPE) and the World Petroleum                  
|              |  | Congresses (WPC). PEMEX estimates proved reserves in compliance with              
|              |  | the definition of proved reserves established by the Securities and Exchange      
|              |  | Commission (SEC).                                                                 
|             
|              |  | It is worth to mention that distinguishing proved reserves from probable and      
|              |  | possible, has the purpose of signaling the identified opportunities and relate    
|              |  | them to different behaviors, or exploitation strategies, in the discovered fields.
|             
|              |  | Additionally, PEMEX has a central group that allows the company to                
|              |  | internally certify the reserves and to sanction, technically and economically,    
|              |  | the restatements and discoveries done during a given period of time;              
|              |  | independently from the evaluations done by PEMEX Exploration and                  
|              |  | Productions business units and according to a process established and            
|              |  | known in the whole organization.                                                  
|             
|Adoption of   |  | In 2002, PEMEX adopted the criteria of the Securities and Exchange                
|the SEC       |  | Commission (SEC) for the definition of proved reserves and the estimation         
|criteria for  |  | was applied retroactively since 1998. It is worth saying that the application of  
|proved        |  | these criteria did not modify the measurement of total, or 3P reserves, it only   
|reserves      |  | modified its composition, decreasing proved reserves and increasing               
|              |  | probable and possible reserves. These types of reserves will be defined           
|              |  | further on.                                                                       
|              |  |                                                                                   
|Figure 1     





|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|External    |  | Since 1996, PEMEX has retained internationally recognized external           
|----------- |  | -----------------------------------------------------------------------------
|Consultants |  | consultants specialized in reserves to review its reserve calculations.      
|           
|            |  | These consultants have certified the estimates made by PEMEX, which          
|            |  | entails the independent evaluation of the original volume in place and the   
|            |  | associated hydrocarbon reserve. In May 2004, the Board of Directors of       
|            |  | PEMEX Exploration and Production approved a proposal to have external        
|            |  | consultants annually certify the hydrocarbon reserves.                       
|           
|            |  | Currently, external consultants are reviewing the reserves as of December 31,
|            |  | 2004. This process is expected to conclude during the third quarter of 2005. 

|Definition |  | The terms original volumes, prospective and contingent resources and           
|---------- |  | -------------------------------------------------------------------------------
|criteria   |  | reserves have been established in accordance with several organizations        
|           |  | related to the industry, for example, the Society of Petroleum Engineers       
|           |  | (SPE) and the American Association of Petroleum Geologists (AAPG); and         
|           |  | also by national committees, like the World Petroleum Congresses (WPC).        
|           |  | Additionally as previously mentioned, PEMEX estimates proved reserves in       
|           |  | compliance with the definition of proved reserves established by the           
|           |  | Securities and Exchange Commission (SEC).                                      
|          
|           |  | The evaluation of reserves is a process of estimation of volumes in            
|           |  | hydrocarbon reservoirs that cannot be measured in an exact manner. The         
|           |  | accuracy of any reserves estimation depends on the quality of the             
|           |  | information available. Furthermore, subsequent results of drilling, testing and
|           |  | production could generate revisions to the initial estimation.                 
|          
|           |  | The use of these definitions allows PEMEX to distinguish among different       
|           |  | types of reserves and provide reports of reserves consistent with international
|           |  | practices.                                                                     

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                
|Figure 2                                        

|SEC definition |  | Proved reserves are estimated volumes of hydrocarbons which geological        
|-------------- |  | ------------------------------------------------------------------------------
|of proved      |  | and engineering analysis demonstrates with reasonable certainty will be       
|reserves       |  | commercially recoverable in future years from known reservoirs under the      
|               |  | prevailing economic conditions, operational methods and government            
|               |  | regulations.                                                                  
|              
|Definition of  |  | In addition to proved reserves, PEMEX considers probable and possible         
|probable and   |  | reserves to constitute total reserves, also called 3P reserves.               
|possible       |  |                                                                               
|reserves       |  | Probable reserves are those where the analysis of the geological and          
|               |  | engineering information of these reservoirs suggests that they are more likely
|               |  | to be commercially recoverable than otherwise. If probabilistic methods are   
|               |  | employed for its evaluation, there is a probability of at least 50% that the  
|               |  | amounts to be recovered will be equal to or greater than the sum of proved    
|               |  | plus probable reserves, also called 2P reserves.                              
|               |  |                                                                               
|               |  | With regard to possible reserves, these are volumes of hydrocarbons whose     
|               |  | geological and engineering information suggests that their commercial         
|               |  | recovery is less certain than that of the probable reserves. According to this
|               |  | definition, when probabilistic methods are employed, there is a probability of
|               |  | at least 10% that the amounts actually recovered will be equal to or greater  
|               |  | than the sum of proved, probable and possible reserves, or 3P reserves.       
|               |  |                                                                               

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Proved      |  | Based upon these definitions, as of December 31, 2004, PEMEX estimates proved        
|----------- |  | -------------------------------------------------------------------------------------
|reserves at |  | reserves of 17 thousand 650 million barrels of crude oil equivalent, of which 73%    
|the end of  |  | represents crude oil, 11% represents condensates and liquids from plants and the     
|2004        |  | remaining 16% represents dry gas.                                                    
|           
|            |  | Of total proved reserves, 11 thousand 346 million barrels of crude oil equivalent, or
|            |  | 64%, are developed, which means reserves that are expected to be recovered from      
|            |  | existing wells, including the reserves that can be recovered utilizing the current   
|            |  | infrastructure through additional works at moderate investment costs. These          
|            |  | reserves are located at the off-shore regions and on the onshore regions of          
|            |  | southeast Mexico. Among the most important fields are Akal, Jujo-Tecominoacán        
|            |  | and the fields of the Antonio J. Bermúdez and Ku-Maloob-Zaap complexes.              
|           
|            |  | The remaining 6 thousand 304 million barrels of crude oil equivalent correspond to   
|            |  | undeveloped proved reserves, which means volumes that are expected to be             
|            |  | produced through drilling wells in the future. These volumes represent 36% of        
|            |  | proved reserves and are mainly located in Akal, Jujo-Tecominoacán, Maloob,           
|            |  | Zaap, Chicontepec, Sinán, May y Misión (the latter three of the Light Crude Oil      
|            |  | Marine project).                                                                     
|           
|Figure 3   

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Probable    |  | Probable reserves were estimated to total 15 thousand 836 million barrels of crude 
|----------- |  | -----------------------------------------------------------------------------------
|and         |  | oil equivalent, which together with proved reserves constitute a 2P reserve of 33  
|possible    |  | thousand 486 million barrels of crude oil equivalent. Probable reserves volumes    
|reserves at |  | are mainly located in the fields Akal, Ku, Maloob, Zaap and Chicontepec.           
|the end of  |  |                                                                                    
|2004        |  | Moreover, possible reserves were estimated to total 13 thousand 428 million        
|            |  | barrels of crude oil equivalent which, when added to proved and probable reserves, 
|            |  | constitute a 3P reserve of 46 thousand 914 million barrels of crude oil equivalent.
|            |  | An important volume of the possible reserves is located in the Chicontepec field.  
|            |  |                                                                                    
|            |  | Of the total 3P reserves, 71% represents crude oil, 9% condensate and liquids from 
|            |  | plants and 20% represents dry gas equivalent to liquid.                            
|Figure 4   

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Crude oil |  | With regards to crude oil, proved reserves were estimated to total 12 thousand 882   
|--------- |  | -------------------------------------------------------------------------------------
|reserves  |  | million barrels, of which 64% represents heavy crude oil, 30% represents light       
|          |  | crude oil and the remaining 6% represents extralight crude oil.                      
|         
|          |  | It is important to note that heavy crude is determined by a density less than or     
|          |  | equal to an API gravity of 27°, light crude is determined by an API gravity greater  
|          |  | than 27° but less than or equal to 38° and extralight crude by an API gravity greater
|          |  | than 38°.                                                                            
|         
|          |  | In the aggregate, the 3P crude oil reserves totaled 33 thousand 312 million barrels, 
|          |  | of which 52% represents heavy crude oil, 37% represents light crude oil and the      
|          |  | remaining 11% represents extralight crude oil.                                       
|         
|Figure 5 

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Natural gas |  | Proved natural gas reserves were estimated to total 20,433 billion cubic feet, of
|----------- |  | ---------------------------------------------------------------------------------
|reserves    |  | which 69% represents associated gas and 31% represents non-associated gas.       
|           
|            |  | 3P reserves of natural gas were estimated to total 63,879 billion cubic feet, of 
|            |  | which 77% represents associated gas and the remaining 23% represents non-        
|            |  | associated gas.                                                                  
|           
|Figure 6   

|        
|--------
|On shore
|and     
|offshore
|reserves
|        
|        
|        
|        

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                
|Figure 7                                        



|Reserve-   |  | The reserves-production ratio, which is the ratio resulting from dividing the estimated
|---------- |  | ---------------------------------------------------------------------------------------
|production |  | reserves as of December 31, 2004 by the total production of 2004 is equivalent to 29   
|ratio      |  | years for the 3P reserves, 21
years for the 2P reserves and 11 years for the proved    
|           |  | reserves. In all three cases, the reserves-production ratio decreased one year as      
|           |  | compared to the same indicator estimated at the end of 2003.                           
|Figure 8  

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Evolution |  | The change in 3P reserves is the result of the volume produced, which is being offset 
|--------- |  | --------------------------------------------------------------------------------------
|of        |  | by the exploratory activity, revisions, developments and delineations of existing     
|reserves  |  | fields. Since the year 2000, PEMEX has increased its investments in exploration,      
|          |  | which has allowed PEMEX reduce the rate at which reserves decrease thanks to          
|          |  | new discoveries resulting from exploration activity.                                  
|         
|          |  | From 2003 to 2004, the decrease in 3P reserves was 1,127 million barrels of crude     
|          |  | oil equivalent, even though production during the period was 1,611 million barrels of 
|          |  | crude oil equivalent. Further ahead I will describe in detail the manner in which this
|          |  | decrease was constituted considering discoveries, developments, delineations and      
|          |  | revisions.                                                                            
|          |  |                                                                                       
|Figure 9 



|Evolution |  | In 2004, crude oil 3P reserves decreased 1,077 million barrels of crude oil            
|--------- |  | ---------------------------------------------------------------------------------------
|of crude  |  | equivalent, this was mainly due to the production of 1,238 million barrels of crude oil
|oil       |  | equivalent. Proved reserves decreased 1,237 million barrels of crude oil equivalent.   
|reserves  |  | 2P reserves decreased 193 million barrels of crude oil equivalent as a result of       
|          |  | restatements and development of fields, mainly in Citam. Possible reserves             
|          |  | increased 354 million barrels of crude oil equivalent due to restatements and          
|          |  | discoveries.                                                                           
|          |  |                                                                                        

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                
|Figure 10                                       

|Evolution of gas |  | Even though natural gas production in 2004 was 1.7 trillion cubic feet, there       
|---------------- |  | ------------------------------------------------------------------------------------
|reserves         |  | was not a significant decrease in 3P reserves. This is mainly due to the effect     
|                 |  | of discoveries and the developments of non-associated gas fields.                   
|                
|                 |  | The increase in non-associated natural gas reserves (dry gas and wet gas) are       
|                 |  | consequence of the intense development of the fields in the Burgos and              
|                 |  | Veracruz Basins, were reserves increased by 526 billion cubic feet, mainly in       
|                 |  | the Arcabuz, Caudaloso, Culebra, Fundador, Velero and Apértura fields.              
|                
|                 |  | The decrease of proved reserves was only 0.3 trillion cubic feet, or 1.5%           
|                 |  | compared to 2003 reserves, considering production.                                  
|                
|2004 vs. 2003    |  | In 2004, proved reserves decreased by 1,245 millions of barrels of crude oil        
|reserves         |  | equivalent with respect to the previous year, 2P reserves decreased by 1,414        
|                 |  | millions of barrels of crude oil equivalent and 3P reserves decreased by 1,127      
|                 |  | millions of barrels of crude oil equivalent. It is important to note that the driver
|                 |  | of the change is a production level of 1,611 million barrels of crude oil           
|                 |  | equivalent.                                                                         

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                
|Figure 11                                       



|Discoveries     |  | Discoveries refer to the incorporation of reserves attributable to successful      
|--------------- |  | -----------------------------------------------------------------------------------
|                |  | exploratory wells drilled in new reservoirs.                                       
|               
|                |  | In 2004, discoveries of proved reserves totaled 241 million of barrels of crude    
|                |  | oil equivalent, 2P discoveries totaled 463 million barrels of crude oil equivalent 
|                |  | and 3P discoveries totaled 916 million barrels of crude oil equivalent,            
|                |  | concentrated in the Samaria, Wayil, Tumut, Pohp, Baksha, Pokoch and Tizón          
|                |  | fields in the Southeast Basins; Bagre in the Tampico-Misantla Basin and            
|                |  | Santander in the Burgos Basin.                                                     
|               
|Discoveries and |  | Discoveries and delineations of proved reserves totaled 369 million barrels of     
|delineations    |  | crude oil equivalent, 2P discoveries and delineations totaled 678 million barrels  
|                |  | of crude oil equivalent and 3P discoveries and delineations totaled 1,234          
|                |  | million barrels of crude oil equivalent.                                           
|               
|Developments    |  | Developments and delineations refer to increases or reductions of reserves as      
|                |  | a consequence of development and delineation wells drilled.                        
|               
|                |  | The increase in the 1P reserve due to developments of fields totaled 208           
|                |  | million barrels of crude oil equivalent, of 2P reserves totaled 119 million barrels
|                |  | of crude oil equivalent and of 3P reserves, which is the aggregation of proved,    
|                |  | probable and possible reserves, totaled negative 82 million barrels of crude oil   
|                |  | equivalent.                                                                        

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Revisions       |  | Revisions are the result of considering new information including geological,  
|--------------- |  | -------------------------------------------------------------------------------
|                |  | geophysical, operational and reservoir behavior, as well as the variation in   
|                |  | hydrocarbon prices and lifting costs.                                          
|               
|                |  | Downward revisions of proved reserves totaled 211 million barrels of crude oil 
|                |  | equivalent. For probable reserves, the revisions totaled negative 390 million  
|                |  | barrels of crude oil equivalent and for possible reserves, revisions totaled   
|                |  | negative 66 million barrels of crude oil equivalent.                           
|               
|                |  | These decreases were mainly concentrated in fields like Kutz, Samaria,         
|                |  | Oxiacaque y Abkatún. These reductions were identified by analyzing the         
|                |  | behavior in terms of pressure, production and water presence in these fields.  
|               
|                |  | In order to reverse this effect, PEMEX has begun a pressure maintenance        
|                |  | program through the injection of nitrogen in the Samaria and Oxiacaque fields  
|                |  | which is programmed to start in 2007. For the Abkatún field the pressure       
|                |  | maintenance will be done through water injection and currently electronic      
|                |  | centrifuge pumping equipment is being installed in the wells of the fields.    
|               
|Production      |  | In 2004, production was 1,611 million barrels of crude oil equivalent          
|               
|Proved reserves |  | In conclusion, the variation of proved reserves shows a stable behavior. On    
|balance as of   |  | the one hand there are increases attributable to discoveries and developments  
|2004            |  | in existing fields, plus positive delineations resulting from the exploratory  
|                |  | activity. Nevertheless, there have been some negative revisions, as previously 
|                |  | mentioned.                                                                     
|               
|                |  | Considering the current information available, there are no negative changes in
|                |  | the existing reserves in the immediate future.                                 

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Reserves         |  | It is important to remember that the reserves replacement rate is defined as the
|---------------- |  | --------------------------------------------------------------------------------
|replacement rate |  | ratio resulting from dividing the discovered reserves -1P, 2P or 3P- by the     
|                 |  | production in a given period without taking into account developments,          
|                 |  | delineations and revisions.                                                     
|                
|                 |  | Considering discoveries of 3P reserves in 2004, 916 million barrels of crude oil
|                 |  | equivalent, the reserves replacement rate is 57% compared to 45% in 2003.       
|                
|                 |  | The integrated reserves replacement rate of proved reserves  allowing for      
|                 |  | discoveries, developments and revisions  was 23%, compared to 26% in           
|                 |  | 2003.                                                                           
|                
|                 |  | Applying this analysis to natural gas, the integrated reserves replacement rate 
|                 |  | of proved reserves is 82%. This indicator reflects the investment oriented to   
|                 |  | natural gas fields developments and exploration in recent years.                
|                
|Figure 12       

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Reserves         |  | Taking into account information as of December 31, 2004, a level of investment    
|---------------- |  | ----------------------------------------------------------------------------------
|replacement      |  | in exploration and production of about 10 billion dollars in the next 5 years with
|goals            |  | an increase in the proportion allocated to exploration, our expected goal is to   
|                 |  | achieve a 3P reserve replacement rate of 65 per cent in 2006 and 100 per cent     
|                 |  | in 2010.                                                                          
|                
|                 |  | Likewise, our goal for the integrated reserves replacement rate of proved         
|                 |  | reserves will gradually increase to reach 77 per cent in 2010. Please note that   
|                 |  | towards 2007, PEMEX expects developments from the projects Ku-Maloob-             
|                 |  | Zaap, Crudo Ligero Marino and Chicontepec that will permit increasing the         
|                 |  | integrated reserves replacement rate of proved reserves by important              
|                 |  | reclassifications from probable reserves to proved reserves.                      
|                
|                 |  | These goals correspond to a scenario given by expected values that consider       
|                 |  | uncertainty and the risk associated to the activities of exploration and          
|                 |  | production of hydrocarbons as of December 31, 2004.                               
|                
|Main discoveries |  |                                                                                   
|                
|Discoveries      |  | The investments made by PEMEX in the period from 2001 to 2003 have                
|2001-2003        |  | resulted in the incorporation of 1,536 million barrels of crude oil equivalent of 
|                 |  | 3P reserves.                                                                      
|                
|                 |  | The priority for PEMEX in these years has been to incorporate reserves of         
|                 |  | non associated gas and crude oil, underscoring the non associated gas             
|                 |  | discoveries of 897 million barrels of crude oil equivalent within the 3P          
|                 |  | reserves, concentrated in the off-shore fields of Lankahuasa in the Tampico-      
|                 |  | Misantla Basin, Chukua y Akpul in the Southeast Basins, and the on-shore          
|                 |  | fields of Nejo and Enlace in the Burgos Basin and Lizamba and Vistoso in          
|                 |  | the Veracruz Basin. Of these discoveries, 152 million barrels of crude oil        
|                 |  | equivalent are proved reserves.                                                   
|                
|                 |  | In relation to crude oil, it is important to highlight the discoveries of 639     
|                 |  | million barrels of crude oil equivalent within the 3P reserves, from the off-     
|                 |  | shore fields of Misión y Amoca in the Southeast Basins and Lobina in the          
|                 |  | Tampico-Misantla Basin; as well as the on-shore fields Shishito and the           
|                 |  | Naranja block of the Sen field in the Southeast Basins. Of these                  
|                 |  | discoveries, 145 million barrels of crude oil equivalent are proved reserves.     

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                
|Figure 13                                       

|2004 discoveries | In 2004, discoveries are mainly concentrated in:                            
|---------------- | ----------------------------------------------------------------------------
|                
|                 | •                                                                           
|                 |                                                                             
|                 |                                                                             
|                 | •                                                                           
|                 |                                                                             
|                 |                                                                             
|                 | •                                                                           
|                 |                                                                             
|                 |                                                                             
|                
|                 | Of the total discovered in 2004, 70% represents crude oil reservoirs and the
|                 | remaining 30% represents non-associated gas, within the 3P reserves. 1P     
|                 | discoveries represent 26% of 3P discoveries. This percentage should         
|                 | increase with developments and delineations, as is currently happening at   
|                 | the Burgos and Veracruz Basins.                                             

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                
|Figure 14                                       

|Main off-shore | In 2004 PEMEX continued to explore the waters in the Gulf of Mexico.           
|-------------- | -------------------------------------------------------------------------------
|discoveries    | Crude oil discoveries of 3P reserves were estimated to represent 459 million   
|               | barrels of crude oil equivalent, mainly from drilling the wells Wayil-1, Tumut-
|               | 1, Pohp-1 and Baksha-1, from the Southeast Basins. Of this total, 150          
|               | million barrels of crude oil equivalent are proved reserves.                   
|              
|               | The discoveries of non-associated gas represented 111 million barrels of       
|               | crude oil equivalent of 3P reserves, mainly from drilling the wells Men-1,     
|               | Poctli-1 and Után-1 from the Southeast Basins and Kosni-1 from the             
|               | Tampico-Misantla Basin. Out of this, 39 million barrels oil equivalent are     
|               | proved reserves.                                                               
|              
|Main onshore   | In 2004, the main onshore discoveries were:                                    
|discoveries    |                                                                                
|               | •                                                                              
|               |                                                                                
|               |                                                                                
|               |                                                                                
|               | •                                                                              
|               |                                                                                
|               |                                                                                
|               |                                                                                
|               |                                                                                
|               |                                                                                

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Future strategy   |  | The emphasis in exploration efforts have been in reservoirs located in             
|----------------- |  | -----------------------------------------------------------------------------------
|of exploration    |  | known basins. Starting 2004, this emphasis has been reinforced with the            
|                  |  | location of exploratory opportunities in zones away from the ones                  
|                  |  | traditionally explored. These include deep waters through the acquisition          
|                  |  | and interpretation of three-dimensional seismic information.                       
|                 
|                  |  | It is important to mention that this exploratory strategy reflects an              
|                  |  | equilibrated portfolio with moderate and high risk exploration opportunities       
|                  |  | were the volume to incorporate is significant and strategical for PEMEX, and       
|                  |  | is oriented to non-associated gas and light crude oil.                             
|                  |  |                                                                                    
|                  |  |                                                                                    
|                 
|                 
|Clarifying points
|                 
|CAPEX in          |  | In the next years, PEMEX expects to sustain exploration investments at             
|exploration       |  | between US$ 1.5 and 2 billion per year, which is comparable to the                 
|                  |  | exploration investments realized in 2004.                                          
|                 
|Proved            |  | It is expected that the rate of proved integrated reserves replacement rate will   
|integrated        |  | increase from 23% in 2004 to 77% by 2010 (including discoveries,                   
|reserves          |  | developments, delineations and revisions).                                         
|replacement       |  |                                                                                    
|rate              |  | The most important factor in the increase of the reserve replacement is the        
|                  |  | construction of the infrastructure for the development of Ku-Maloob-Zaap,          
|                  |  | Crudo Ligero Marino and Chicontepec, which are expected to allow a                 
|                  |  | reclassification of probable and possible reserves to proved reserves, which is    
|                  |  | in accordance with Securities and Exchange Commission definitions.                 
|                 
|Production        |  | Currently, PEMEX produces 3.4 million barrels per day of crude oil and 4.7         
|                  |  | billion cubic feet per day of natural gas. It is estimated a similar production for
|                  |  | 2005.                                                                              
|                 
|                  |  | Likewise, with the development of projects such as Ku-Maloob-Zaap, Crudo           
|                  |  | Ligero Marino and Chicontepec, PEMEX expects a production of 4 million             
|                  |  | barrels per day of crude oil and 6 billion cubic feet per day of natural gas in    
|                  |  | 2008                                                                               

|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Cantarell     |  | In 2004, crude oil production in Cantarell was 2.1 million barrels per day,   
|------------- |  | ------------------------------------------------------------------------------
|              |  | while natural gas production was 740 million cubic feet per day. As of        
|              |  | December 31, 2004, proved and probable reserves (2P) in Cantarell             
|              |  | amounted 7,965 million barrels of oil equivalent, while proved reserves       
|              |  | amounted 6,593 million barrels of oil equivalent.                             
|             
|              |  | A strict monitoring and management reserves program is followed in each of    
|              |  | Cantarells wells. This monitoring allows PEMEX to estimate its production    
|              |  | levels, which is estimated to start declining by the end of this year.        
|             
|Deep waters   |  | Only 33 million barrels of crude oil equivalent from discoveries in deep water
|              |  | (ocean depth of more than 500 meters) were included in the 2004 total         
|              |  | reserves (3P).                                                                
|             
|              |  | These reserves came from the Nab-1 well, which was drilled at an ocean        
|              |  | depth of 681 meters in the Gulf of Mexico. All other discoveries and reserves 
|              |  | are in waters of less than 500 meters depth, or on shore.                     
|             
|Drilling      |  | In 2004, 727 wells were drilled and finished, of those 103 were exploratory   
|              |  | wells.                                                                        
|             
|Lifting costs |  | PEMEXs lifting costs are approximately US$ 3 per barrel in shallow waters    
|              |  | (less than 500 meters).                                                       
|              |  |                                                                               
|             
|              |  |                                                                               

|                                                                             
|-----------------------------------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**                             
|www.pemex.com                                                                
|PEMEX                                                                        
|                                                                             
|Annex                                                                        
|Table A1
        Historic evolution of Mexican mix crude oil and sour wet gas



|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Table A2Reservoirs
discovered
in
2004
|-------------------------------------
|                                     
|                                     
|                                     
|                                     
|Basin Field                          
|                                     
|Total                                
|                                     
|Burgos                               
|Azabache                             
|Bayo                                 
|Cañón                                
|Casta                                
|Cúpula                               
|Nejo                                 
|Pame                                 
|Santander                            
|Talud                                
|Tequis                               
|Vagabundo                            
|Visir                                
|                                     
|Sabinas                              
|Forastero                            
|                                     
|Sureste                              
|Baksha                               
|Etkal                                
|Itla                                 
|Men                                  
|Nab                                  
|Numán                                
|Poctli                               
|Pohp                                 
|Pokoch                               
|Samaria                              
|Tizón                                
|Tumut                                
|Után                                 
|Wayil                                
|                                     
|Tampico-Misantla                     
|Atún                                 
|Bagre B                              
|Kosni                                
|                                     
|Veracruz                             
|Apértura                             
|Arquimia                             
|Lizamba                              
|Lizamba                              
|Madera                               





|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                

|Table A6 Hyodrocarbon reserves as of December 31, 2004
|------------------------------------------------------
|                                                      
|                                                      
|                                                      
|                                                      
|                                                      
|                                                      
|                                                      
|Total (3P)                                            
|Proved                                                
|Probable                                              
|2P                                                    
|Posible                                               
|                                                      

|*                                                                                                            | Gas liquids from processing plants.                                                                                                                  
|------------------------------------------------------------------------------------------------------------ | -----------------------------------------------------------------------------------------------------------------------------------------------------
|**                                                                                                           | The liquid obtained supposes a heat value equivalent to the Maya crude oil and an average mixture of the
dry gas obtained at Cactus, Ciudad PEMEX and
|NuevoPEMEXgasprocessingcenter.                                                                              
|Note: All the units are expressedatatmosphericconditionsandassume15.6oC and 14.7 lb ofpressurepersquareinch.



| | Table A6
    Hydrocarbon reserves                                                                          
| | -----------------------------------------------------------------------------------------------------------
| |                                                                                                            
| |                                                                                                            
| |                                                                                                            
| |                                                                                                            
| |                                                                                                            
| |                                                                                                            
| |                                                                                                            
| |                                                                                                            
| | Total                                                                                                      
| | Cantarell                                                                                                  
| | Ku-Maloob-Zaap                                                                                             
| | Abkatún-Pol-Chuc                                                                                           
| | Litoral de Tabasco                                                                                         
| | Burgos                                                                                                     
| | Poza Rica-Altamira                                                                                         
| | Veracruz                                                                                                   
| | Bellota-Jujo                                                                                               
| | Cinco Presidentes                                                                                          
| | Macuspana                                                                                                  
| | Muspac                                                                                                     
| | Samaria-Luna                                                                                               
| |                                                                                                            
| | Note: All the units areexpressedatatmosphericconditionsandassume15.6oC and 14.7 lb ofpressurepersquareinch.



|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   
|PEMEX                                           
|                                                





|PEMEX is Mexicos national oil and gas company. Created in 1938, it is the exclusive producer of Mexicos oil and gas resources. The operating subsidiary entities are PEMEX Exploration and Production, PEMEX Refining, PEMEX Gas and Basic Petrochemicals and PEMEX Petrochemicals. The principal subsidiary company is PMI, its international trading arm.
      This report contains forward-looking statements. Statements that are not historical facts, including statements about our beliefs and expectations, are forward looking-statements. These are good faith statements based on current plans, estimates and projections and therefore you should not place undue reliance on them. Forward-looking statements speak only as of the date they were made, and we undertake no obligation to update publicly any of them in light of new information or future events. Forward-looking statements involve inherent risks and uncertainties. These risks and uncertainties include crude oil price volatility; production, equipment, and transportation risks inherent in the oil industry; environmental regulations in Mexico; actions of the Mexican government with respect to our operations, budget, taxation, commercial activities, control of hydrocarbon reserves, or debt service payments; any limitations on exports resulting from agreements of the Mexican government; and economic, political, and foreign exchange risks affecting Mexico. These risks and uncertainties are more fully detailed in PEMEX most recent Form 20-F filing with the US Securities and Exchange Commission (www.sec.gov) and the PEMEX Prospectus filed with the National Banking and Securities Commission (CNBV) and available through the Mexican Stock Exchange (wwww.bmv.com.mx). These factors could cause actual results to differ materially from those contained in any forward-looking statement.
      The US Securities and Exchange Commission (SEC) permits oil and gas companies, in their filings with the SEC, to disclose only proved reserves that a company has demonstrated by actual production or conclusive formation tests to be economically and legally producible under existing economic and operating conditions. We use certain terms in this document, such as total reserves, probable reserves and possible reserves, that the SEC's guidelines strictly prohibit us from including in filings with the SEC. Investors are urged to consider closely the disclosure in our Form 20-F, File No. 0-99, available from us atwww.pemex.comor Marina Nacional 329 Floor 38 Col. Huasteca, Mexico City 11311 or at (52 55) 1944 9700. You can also obtain this Form from the SEC by calling 1-800-SEC-0330.
      EBITDA, free cash-flow and discretionary cash-flow are non-GAAP measures, which are calculated as described above. They are presented because PEMEX believes that they are widely accepted financial indicator of its ability to service or incur debt. EBITDA, free cash-flow and discretionary cash-flow should not be considered as indicators of financial performance, as an alternative to cash flow, as a measure of liquidity, or as being comparable to similarly named measures of other companies.
    The total debt calculation includes, in addition to documented debt, the items that are usually considered as debt by the financial markets.
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------







|                                                
|------------------------------------------------
|**Hydrocarbon reserves as of December 31, 2004**
|www.pemex.com                                   

---

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

| | Petróleos Mexicanos                                                                                       
| | ----------------------------------------------------------------------------------------------------------
| | By: /s/ Octavio Ornelas Esquinca Octavio Ornelas Esquinca
       Managing Director of Finance and Treasury



Date: April 20, 2005

FORWARD-LOOKING STATEMENTS