Adding family planning and population programs to the list of tropical medicine components expands the definition of what might be called appropriate medicine for the developing countries. This comprehensive definition covers the topics of prime importance to the health and ultimate development of preindustrial societies. These topics are given low priority in all medical education. Nutrition has been left to the schools of public health. Schools of agriculture are interested in the quality and quantity of food production but not in the social and economic complexities of relating food production to the nutritional status of the population to be served. the variables are interdependent. In the world more than 3 billion people live on the margin of existence. High mortality contributes to high fertility rates because living children are the only available form of social security. Food production cannot keep pace. Malnutrition is a factor in at least 1/2 of the 45 million global deaths in those less than 5 years of age. In the Far East and Africa 25-30% of the population are undernourished. During the next 15 years the world may add 1 billion people to its present 4 billion and there may be 8 billion shortly after the year 2000. Of these 6.6 billion would be in developing countries. In Africa, South America, and the Middle East, surveys have shown that 96% of 1000 women in the third trimester of pregnancy and 75% of school children in South India were anemic. At least a 4% annual increase in food production is needed between now and the year 2000 to meet the needs of present malnutrition and projected population growth. The prospects of achieving this are not good. Also, of regional importance are vector borne and macroparasitic diseases and trachoma and yaws. Of universal importance are fecally related diseases and air-borne diseases. Malaria still persists in many areas with an estimated 1 million deaths annually. Recently the World Bank has paid increasing attention to provisions for health. In 1976 about 357 million dollrs is proposed for loans and credits for health-related projcts. Intra- and transnational migration of human populations is steadily increasing and has and will continue to spread disease. The potential for mass epidemics remains. Our global responsibility for training of public health workers from and for developing countries remains. Food, population, and health are the major independent variables in the global equation for the quality of life. The control of transmissible disease remains a vital undertaking for the American health establishment. We live in an increasing interdependent world. Many people and nations look to the U.S. to sustain its leadership in biomedical research and medical and public health education. An interdependent world cannot afford the stresses of ill health, poverty, and explosive population growth. We need resurgence of interest in public health, tropical medicine, and a change in individual and national life styles.