Page 1 January 4, 1996 Mr. Martin Werner Director General de Credito Publico Secretaria de Hacienda y Credito Publico Insurgentes Sur 826, Piso 9 03100 Mexico, D. F. Re: Loan No. 3912-ME (Essential Social Services Program) Amendment to the Guarantee Agreement Dear Sir: Please refer to the Guarantee Agreement between International Bank for Reconstruction and Development (the Bank) and the United Mexican States (the Guarantor) dated June 23, 1995 (the Guarantee Agreement). We are pleased to inform you that, as a result of our recent discussions on the subject, the Bank agrees to amend the Guarantee Agreement as follows: Preamble WHEREAS clause (B) of the Preamble on page 1 of the Guarantee Agreement is hereby amended by replacing the words "various currencies equivalent" with the words "an amount equal". Section 1.01 This Section is hereby amended by replacing the words "The "General Conditions Applicable to Loan and Guarantee Agreements" of the Bank, dated January 1, 1985," with the words "The "General Conditions Applicable to Loan and Guarantee Agreements for Single Currency Loans" of the Bank, dated May 30, 1995,". Please confirm your agreement to the foregoing amendment by signing and dating this letter in the spaces provided below. This amendment letter may be executed in two counterparts, each of which shall be an original. Upon your confirmation, please return one fully executed original to us. The provisions of this amendment letter will become effective upon receipt by the Bank of said fully executed original. Very truly yours, INTERNATIONAL BANK FOR RECONSTRUCTION AND DEVELOPMENT Martin J. Staab Acting Director Country Department II Latin America and the Caribbean Region UNITED MEXICAN STATES By: Martin Werner Authorized Representative Date: Enero 31, 1996 Page 2