**Exhibit 99-3**



SOCIAL
COMMUNICATIONS CORPORATE MANAGEMENT



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# BULLETIN N° 191 / 2004

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DATE: 08/ 19/ 2004

**PEMEX INCREASES FOREIGN
EXCHANGE INCOME FROM CRUDE OIL SALES ABROAD**

| | • |  | **From January to July 2004, Pemex obtained U.S. $1.845 billion more compared to the same
                               period last year**
| | - |  | -------------------------------------------------------------------------------------------------------------------------------------------
| | • |  | **As of July, the company changed the methodology for reporting its income due to crude oil
 exports**                                     
| | • |  | **The new methodology does not affect in any way the financial statements nor the accounting of Pemex**                                    

By
exporting an average volume of 1,833 thousand barrels of crude oil per day,
Petróleos Mexicanos generated an income of foreign exchange of a total of U.S.
$11.308 billion during the period from January to July, 2004, an amount greater by U.S.
$1.845 billion compared to the amount obtained for the aforementioned concept during the
same period last year.

It
is important to inform that as of the month of July, Pemex shall publish in its Oil
Indicators the statistical figures of the operative figures of each month. Thus,
Pemex published today in its Oil Indicators an adjustment in the export
figures, as it changed the methodology of averages that it had been applying for another
that shall use as basis the real loading volume performed each month.

The
variability shown by the figures is due to several operative factors, such as: climatic or
meteorological, shipment delays, greater demand in the domestic market, cancellations
derived from force majeure events and, non-programmed stoppages in the crude oil
production processes.

Therefore,
it is important to highlight that the variations reported in the foreign trade of crude
oil, do not modify the total figures previously published and the change in methodology
does not affect in any way whatsoever Pemexs financial statements nor its
accounting. Neither do they affect any reports filed before financial entities, such as
the National Banking and Securities Commission, the United States of America Securities
and Exchange Commission (SEC), the Public Accounting Office, the Ministry of Finance,
banks or investors, among others.

Based
on the Oil Indicators from July, during the months of reference,
Petróleos Mexicanos, through PMI International Commerce, sold to Mexican customers
within the Americas, Europe and the Far East, an average of 1,609 thousand barrels per day
of Maya crude oil, for a total amount of U.S. $9.621 billion.

Regarding
external sales of Isthmus light crude oil made during the first seven months of this year
to these three geographical regions, PEMEX placed an average volume of eight thousand
barrels per day, with a total value of U.S. $59 million.

Regarding
the export of Olmeca extra-light crude oil, which due to its quality and price has great
acceptance in the international market, during the months from January to July of this
year, PMI sold abroad a volume averaging 216 thousand barrels per day, for a total amount
of U.S. $1.628 billion.

The
average export sales price of the Mexican crude oils during the period from January to
July, 2004 closed at U.S. $34.21 per barrel for the Isthmus light crude oil. The Maya type
was sold at U.S. $28.08 per barrel and the Olmeca extra-light crude oil was sold at U.S.
$35.40 per barrel.

It
is worth mentioning that the weighted average price during the first seven months of this
year was U.S. $28.96 per barrel. This amount represented an increase of U.S. $4.22 dollars
with respect to the value registered during the same period in 2003.

From
the total crude oil exported in the period of reference, 1,616 thousand barrels per day
were addressed to different Mexican customers within the Americas, 173 thousand barrels
were addressed to the European market and 44 thousand barrels per day to the Far East.

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