Abstract-In 2012, the Mexican government declared that Seguro Popular had reached the goal of providing health insurance to nearly 53 million individuals previously not enrolled with social security. This major achievement was reached in only nine years of operation of the new system. However, enormous challenges remain to guarantee that Seguro Popular will provide adequate services to the newly enrolled population. This article uses information collected by four external evaluations of Seguro Popular carried out between 2007 and 2012 to analyze how financial resources are transferred from the federal level to the states and how these resources are used to purchase services on behalf of the affiliated population. We focus on three topics: the financial transfer mechanisms, the purchasing of medicines, and the contracting of health workers. The analysis shows that the implementation of Seguro Popular has confronted major challenges due to limited institutional capacity at the federal and state levels, tension in federal-state relations, limited information systems, the influence of political interests, and the use of financial resources for unauthorized expenditures at the state level. Various legal, normative, and technical changes have been introduced during implementation of Seguro Popular to improve performance, with mixed results. Mexico's experiences with the implementation of health reform may offer important lessons for other countries seeking to expand health coverage.
Keywords: Mexico; health reform; implementation.