June 21, 2006

Exhibit 10.1

June 21, 2006

Ing. Carlos A. Morales Gil

Director General

Petróleos Mexicanos

Avenida Marina Nacional No. 329

Torre Ejecutiva, Piso 41

Colonia Huasteca

México, D.F. 11311


Dear Ing. Morales:

We hereby consent to the references to our firm as set froth in the Annual Report on Form 20-F of Petróleos Mexicanos for the year ended December 31, 2005, under the heading “Exploration andProduction (Reserves)”. We reviewed estimates as of December 31, 2004 of approximately ninety eight (98) percent of the proved crude oil, condensate and natural gas reserves and the oil equivalent of 364 fields with interests owned bythe United Mexican States (“Mexico”). These estimates were prepared in accordance with the reserves definitions of Rules 4-10(a) (1)-(13) of Regulation S-X of the United States Securities and Exchange Commission. The fields arelocated onshore and offshore Mexico in the Northern Region, and are those referenced in our audit letter of July 26, 2005.


Very truly yours,
/s/ Ryder Scott Company, L.P.