Analysis of the 1986 Senegal Demographic and Health Survey reveals that mothers may be able to improve their children's survival chances by migrating from the countryside to the city. Children of urban migrants, however, continue to experience a much higher risk of mortality before the age of 5 than children of urban nonmigrants, even after the mother has lived in the city for several years. This migrant mortality disadvantage persists when controlling for numerous socioeconomic and fertility-related factors typically associated with child mortality in developing countries, which also serve as indicators of migrant selection and adaptation.