Ethnographic studies in West Africa show that the practice of sending children away to be raised by relatives and nonrelatives is widespread among many ethnic groups. This paper is an attempt to explore the demographic relevance of the practice. The fostering information is obtained from two sources: the responses given by women to the question on children away from home, and by linking all children to their mothers with the unmatched children being treated as fosters. The characteristics of these children, their surrogate mothers, and those of the biological mothers are explored, and the determinants of child fostering are discussed as correlates of these attributes. The results are indicative of high incidence of child fosterage in Ghana, Sierra Leone, Liberia and Nigeria. Child fostering enhances female labor force participation, and may affect the fertility decisions of both natural and foster parents, mainly because it serves to reallocate the resources available for raising children within the society. It may also have consequences on child survival, depending partly on how the culture treats children outside of their maternal homes.