This note offers empirical evidence on the Mexican Federal Deputies' influence in the budget process and their lack of monitoring of public spending. Even if the Congress practically abdicated its powers in this respect during the time when the PRI was hegemonic, from the 1980's the legislature has exercised an ever growing budgetary influence. This process, however, has not implied an increased ex post oversight on spending. Once the PRI lost the absolute majority in the Chamber of Deputies, a new era in executive-legislative relations has begun in Mexico. From now on, financial resources will be negotiated between politicians coming from diverse political affiliations, and budgets will only be approved after a complex process of compromise and concession.