Birth to Ten is a longitudinal birth cohort study which began in April 1990 in the Johannesburg/Soweto area of Transvaal, South Africa. In this paper, the reason for the initiation of the study and its location in the current sociopolitical context is discussed. The health status of South Africa children in terms of infant mortality, morbidity (notifiable diseases) and nutritional status is described and mention is made of measures of psychological health and the importance of environmental pollution on health. The existing health service infrastructure in the study area is described and the fragmentation of health services between races, between preventive and curative services and on a geographical basis is highlighted. The study objectives, design, population, inclusion and exclusion criteria, methods of measurement and logistics are described.