The birth prevalence of congenital anomalies in developing countries is similar to that observed in developed countries. However, the health impact of birth defects is higher because of a lack of adequate services for the care of affected infants and a higher rate of exposures to infections and malnutrition. A number of successful measures for the prevention of congenital anomalies are being taken in a number of developing nations. Primary prevention programs are based on public education about preconceptional and prenatal risks. Prevention based on reproduction options includes teratogen information services and prenatal screening for fetal anomalies. In addition, programs for the detection of congenital malformations at birth, followed by early treatment, are contributing to secondary prevention. Prevention of congenital anomalies in the developing world requires: (a) good epidemiological data on the prevalence and types of birth defects and genetic disorders; (b) educating health professionals in the goals and methods of preventing birth defects at low cost but with high impact, and (c) expansion of family planning and improvement of antenatal care combined with educational campaigns to avoid the risks for birth defects. The basis for public health preventive measures should be the primary health care level. In a sizable proportion of developing countries, the stage is already set for these measures to be implemented. Required are education, political will, and proper organization and allocation of resources.