The current available epidemiologic evidence supports a substantial benefit from maintaining a physically active, as compared to a sedentary life-style. Clinician counseling and prescription of regular physical activity should represent a major goal in the treatment and primary prevention of diabetes. This responsibility is of paramount importance, particularly in light of the high prevalence of physical inactivity (based on national survey data, 56% of men and 61% of women in the United States either never or irregularly engage in physical activity), and the high incidence of diabetes and its complications, including severe atherosclerotic disease, in the United States and throughout the world.