The global program of malaria eradication coordinated and supported by the World Health Organization (WHO) since 1957 has been successful in most of the countries in the temperate climate zones of the globe. However, by the end of the 1960s it became evident that technical problems, such as resistance of mosquito vectors to insecticides and resistance of malaria parasites to drugs, presented serious obstacles to the pursuit of eradication programs in many tropical countries. Moreover, the administrative and financial difficulties of the developing countries were such that a revised strategy of antimalaria campaigns became necessary. In 1969 the World Health Organization recommended that although eradication of malaria should remain an ultimate goal, in countries where eradication does not appear to be feasible, malaria control operations may form a transitional stage. All effective methods of attack on the parasite and on the Anopheles vector should be employed according to epidemiological conditions of the area involved and in relation to their technical and logistic feasibility. Nevertheless, during the past decade the malaria situation has deteriorated in several countries, especially in southern and southeast Asia and some parts of Latin America. There has been no improvement in the highly endemic countries of tropical Africa. Since 1978 the concept of primary health care has been widely adopted, and antimalaria activities have become essential components of national health systems in many developing tropical countries. Malaria control within the orbit of primary health care aims first at the reduction of morbidity and mortality from malaria, although the decrease of the prevalence of this infection should also be an objective, whenever possible. This selective approach, based largely on chemotherapy, has been successful in a few countries, but in other areas the degree of integration of antimalaria activities with the primary health care system is less effective. Patterns of such integration depend on different epidemiological, socioeconomic, cultural, and other factors. Malaria control within the framework of primary health care demands full commitment by the government concerned, constant support of the community, and a close cooperation with all other sectors of the health system. Training of national professional and auxiliary staff and health education of the community are equally important.(ABSTRACT TRUNCATED AT 400 WORDS)