This article presents the results of the comparative research project, "Managed Care in Latin America: Its Role in Health System Reform." Conducted by teams in Argentina, Brazil, Chile, Ecuador, and the United States, the study focused on the exportation of managed care, especially from the United States, and its adoption in Latin American countries. Our research methods included qualitative and quantitative techniques. The adoption of managed care reflects the process of transnationalization in the health sector. Our findings demonstrate the entrance of the main multinational corporations of finance capital into the private sector of insurance and health services, and these corporations' intention to assume administrative responsibilities for state institutions and to secure access to medical social security funds. International lending agencies, especially the World Bank, support the corporatization and privatization of health care services, as a condition of further loans to Latin American countries. We conclude that this process of change, which involves the gradual adoption of managed care as an officially favored policy, reflects ideologically based discourses that accept the inexorable nature of managed care reforms.