Mary Story, Karen Kaphingst, and Simone French argue that researchers and policymakers focused on childhood obesity have paid insufficient attention to child care. Although child care settings can be a major force in shaping children's dietary intake, physical activity, and energy balance--and thus in combating the childhood obesity epidemic--researchers know relatively little about either the nutrition or the physical activity environment in the nation's child care facilities. What research exists suggests that the nutritional quality of meals and snacks may be poor and activity levels may be inadequate. Few uniform standards apply to nutrition or physical activity offerings in the nation's child care centers. With the exception of the federal Head Start program, child care facilities are regulated by states, and state rules vary widely. The authors argue that weak state standards governing physical activity and nutrition represent a missed opportunity to combat obesity. A relatively simple measure, such as specifying how much time children in day care should spend being physically active, could help promote healthful habits among young children. The authors note that several federal programs provide for the needs of low-income children in child care. The Child and Adult Care Food Program, administered by the Department of Agriculture, provides funds for meals and snacks for almost 3 million children in child care each day. Providers who receive funds must serve meals and snacks that meet certain minimal standards, but the authors argue for toughening those regulations so that meals and snacks meet specific nutrient-based standards. The authors cite Head Start, a federal preschool program serving some 900,000 low-income infants and children up to age five, as a model for other child care programs as it has federal performance standards for nutrition. Although many child care settings fall short in their nutritional and physical activity offerings, they offer untapped opportunities for developing and evaluating effective obesity-prevention strategies to reach both children and their parents. (Contains 1 table and 109 notes.)