Given the widespread use of out-of-home child care and an all-time high prevalence of obesity among US preschool-aged children, it is imperative to consider the opportunities that child-care facilities may provide to reduce childhood obesity. This review examines the scientific literature on state regulations, practices and policies, and interventions for promoting healthy eating and physical activity, and for preventing obesity in preschool-aged children attending child care. Research published between January 2000 and July 2010 was identified by searching PubMed and MEDLINE databases, and by examining the bibliographies of relevant studies. Although the review focused on US child-care settings, interventions implemented in international settings were also included. In total, 42 studies were identified for inclusion in this review: four reviews of state regulations, 18 studies of child-care practices and policies that may influence eating or physical activity behaviors, two studies of parental perceptions and practices relevant to obesity prevention, and 18 evaluated interventions. Findings from this review reveal that most states lack strong regulations for child-care settings related to healthy eating and physical activity. Recent assessments of child-care settings suggest opportunities for improving the nutritional quality of food provided to children, the time children are engaged in physical activity, and caregivers' promotion of children's health behaviors and use of health education resources. A limited number of interventions have been designed to address these concerns, and only two interventions have successfully demonstrated an effect on child weight status. Recommendations are provided for future research addressing opportunities to prevent obesity in child-care settings.