Pemex Project Funding Master Trust F-4/A Registration of securities (foreign) (amended)

Exhibit 12.2

PETRÓELOS MEXICANOS SUBSIDIARY ENTITIES AND SUBSIDIARY COMPANIES

Computation of ratio of earnings to fixed charges

(Thousands of constant pesos as of June 30, 2005)

	Six Months Ended June 30,
	2005			2004
U.S. GAAP
Fixed Charges(1)
Interest capitalized in fixed assets	Ps.	5,763,703		Ps.	2,828,122
Interest expense		25,176,975			16,034,197
Total interest cost		30,940,678			18,862,319
Total Fixed Charges		30,940,678			18,862,319
Income Earnings after taxes and duties		(10,147,193	)		(8,933,331	)
Fixed Charges(1):
Interest cost net of amounts capitalized		25,176,975			16,034,197
Total Fixed Charges (Net of amounts capitalized)		25,176,975			16,034,197
Earnings after taxes and duties plus fixed charges (net of amounts capitalized)		15,029,782			7,100,866
Amount by which fixed charges exceed earnings	Ps.	15,910,896		Ps.	11,761,453

(1) These figures do not include rental expense.

PETRÓELOS MEXICANOS SUBSIDIARY ENTITIES AND SUBSIDIARY COMPANIES

Computation of ratio of earnings to fixed charges

(Thousands of constant pesos as of June 30, 2005)

	Six Months Ended June 30,
	2005			2004
Mexican GAAP
Fixed Charges(1)
Interest capitalized in fixed assets	Ps.	5,361,068		Ps.	2,211,719
Interest expense		26,133,300			16,650,600
Total interest cost		31,494,368			18,862,319
Total Fixed Charges		31,494,368			18,862,319
Earnings after IEPS taxes and Hydrocarbon Extraction duties		7,044,924			(17,444,180	)
Fixed Charges(1)
Interest cost net of amounts capitalized		26,133,300			16,650,600
Total Fixed Charges (Net of amounts capitalized)		26,133,300			16,650,600
Earnings after taxes and duties plus fixed charges (net of amounts capitalized)		33,178,224			(793,580	)
Amount by which fixed charges exceed earnings	Ps.	(1,683,856	)	Ps.	19,655,899
Ratio of earnings to fixed charges		1.0535

(1) These figures do not include rental expense.