This paper reviews the school-based physical activity (PA) interventions known as health-related physical education (PE), emphasizing the public health benefits for children and adolescents in the USA. The decline of PA with age is well known in children and adolescents, and may affect their future health as well as creating health problems in the immediate term. Although this phenomenon is well accepted in society, little attention has been paid to preventive efforts for the future. In the USA, school PE is seen as an ideal setting for the promotion of regular PA and is also expected to prepare children and adolescents for a lifetime of PA. In this review, the following items are discussed in relation to youth in the USA:1) the perspective of PA decline and national objectives such as Healthy People 2000 and 2010; 2) the evaluation and development of school PE programs to improve current health ; and 3) the potential contribution of school PE to lifelong PA. For maximal public health benefit, the PE has needed a paradigm shift with broad implications, and some multi-component school programs such as Go for Health, CATCH and SPARK have been developed to promote children's PA. In addition, these programs include not only the PA curriculum but also techniques for behavioral change such as goal setting, self-monitoring, and stimulus control to improve children's PA behavior both in and outside school as well as in PE lessons. Finally, the use of an ecological model, emphasized by the perspective of behavioral settings, is introduced to promote PA for children in a school setting.