This paper outlines selected differences between the United States and Latin America health care systems as they relate to primary mental health care. It notes that historically both the United States and Latin America have relied on custodial psychiatric hospitals. The alternative of community care for psychiatric patients is described as it is being implemented in the United States and in developing countries. Striking differences between mental heatlh care in developed and in developing countries are examined, including differences in per capita health care expenditures, patient/psychiatrist ratios, and the distribution of specialized human resources. Population projections for developed and developing nations are given which suggest that by the year 2,000, 80% of the world's population will live in developing countries with insufficient general and mental health services. A section on the current situation examines differences in how the United States and Latin America have attempted to develop new systems of community care. The development of community mental health centers separate from the general health sector in the United States and the development of a system of ambulatory mental health care integrated with the general health sector at the primary care level in Latin America are discussed. The report suggests that the United States study the strategies, strengths, and weaknesses of Latin America's comprehensive model to address its own health care problems more effectively. (NB)