Among the Dogon of Mali, West Africa, 20% of children die in their first year of life and nearly 50% do not survive to age five years. A preliminary study of the causes of this mortality toll has shown that children (N = 176) are significantly more likely to survive if their parents and close paternal relatives are monogamously rather than polygamously married. The goals of this project are twofold: (1) to verify that marital status remains a predictor of child survivorship in a larger sample of over 1000 children, age 0 to 5 years, each of whom will be prospectively monitored for at least two years, and (2) to test alternative explanations for the causes of the relationship between family structure and child mortality. These explanations focus on differences in paternal investment in children, competition among co-wives, the dilution of resources in polygamous families, and the status of women. The results of this study will have practical significance for the problem of child mortality in SubSaharan Africa. They may also help inform other studies of children in poverty.