Backgroud: Although policy approaches are traditionally an important element of public health efforts to address major health problems, public health policy around physical activity remains poorly defined and developed. Methods: After extensive literature searchs and reviews of policy frameworks developed for other public health issues such as tobacco control and injury prevention, the Centers for Disease Control and Prevention hosted a series of workshops and discussions on physical activity policy. Results: A simple model describing relationships among policy, the environment, behavior, and health was developed, a framework for organizing and conceptualizing policy interventions was described, and priorities for public health efforts to promote physical activity were proposed. Conclusions: An expanded focus on physical activity policy interventions is warranted, and such efforts can complement physical activity promotion efforts at other levels. The addition of researchers with expertise in the policity sciences will enhance the work of exisiting multidisciplinary teams.