Unintentional injury is the leading cause of pediatric mortality among American children, but the role of environmental context remains poorly understood as a risk for child injury. Couched in Bronfenbrenner's (1977) ecological theory, this study analyzed data from a sample of almost 900 children to identify relations between the home and out-of-home child care environments and subsequent risk for injury. Results suggest that both child- and supervisor-oriented factors, as measured at 36 months, predicted children's injuries over the subsequent three years. The role of the mesosystem was supported: parent-related factors predicted children's subsequent injuries in child care and school settings, and child care provider experience predicted children's subsequent injuries at home. Results are discussed from the perspectives of ecological theory and implications for injury prevention. Copyright © 2007 by Wayne State University Press.