Physical inactivity increases the risk for heart disease, diabetes, colon cancer, high blood pressure, obesity, osteoporosis, muscle and joint disorders, and symptoms of anxiety and depression. However, approximately one third of adults in the United States report no leisure-time physical activity, and rates of inactivity have been higher in January than in June. Among adults, the prevalence of leisure-time physical inactivity is highest among those who are older, Hispanic, and residing in southern states. A national health objective for the year 2000 is to reduce to < or = 15% the proportion of persons reporting no leisure-time physical activity (objecive 1.5). To assist in monitoring efforts to achieve this objective, CDC analyzed data from the 1994 Behavioral Risk Factor Surveillance system (BRFSS) and estimated for each month the proportion of adults from selected demographic groups who reported no leisure-time physical activity. The findings indicate seasonal patterns in the prevalence of reported leisure-time physical inactivity; however, monthly rates of inactivity were higher and more stable among older persons, Hispanics, and residents of southern states.