Physical inactivity has become a serious problem in the United States. More than half of U.S. adults do not meet recommended levels of moderate physical activity, and one-fourth engage in no leisure time physical activity at all (PHYSICAL ACTIVITY, 1996). Inactivity is more prevalent among those with lower income and education, and, beginning in adolescence, affects females more than males (NIH, 1995; Physical Activity, 1996). A pattern of inactivity, also known as sedentism, begins early in life, making the promotion of physical activity among children imperative. This Digest discusses the importance of and ways to foster activity and exercise in children.