Physical education (PE) can increase student participation in moderate to vigorous physical activity and help high school students gain the knowledge, attitudes, and skills they need to engage in lifelong physical activity. Two national health objectives for 2010 are to 1) increase to >/=50% the proportion of adolescents who participate in daily school PE (objective no. 22-9) and 2) increase to >/=50% the proportion of adolescents who spend at least half of school PE class time being physically active (objective no. 22-10). To examine changes in PE class participation among high school students in the United States during 1991-2003, CDC analyzed data from the national Youth Risk Behavior Survey (YRBS). This report summarizes the results of that analysis, which indicated that 1) the proportion of students attending PE class daily declined significantly during 1991-1995 and did not change during 1995-2003 and 2) the proportion of students exercising or playing sports for >20 minutes during PE class 3-5 days per week did not change significantly during 1991-2003. If the national health objectives are to be achieved, coordinated efforts involving schools, communities, and policy makers are needed to provide daily, quality PE for all youth.