The findings show that participation in any service was associated with positive outcomes, whether the service was voluntary or required. Fifty-five percent of the 4,306 high school students surveyed reported participating in some type of community service. Girls were more likely than boys to be involved in service activities. Older students were more likely to perform service than their younger peers. Participation in any service was associated positively and significantly with grades, civic efficacy, and civic knowledge, as well as negatively with behavior problems. Adolescents who worked directly with individuals in need had better academic adjustment than those who did not; and those who worked for organizations had better civic outcomes than adolescents who performed other types of service. The findings indicate that service activity is one way for schools to foster academic adjustment and civic development among adolescents attending high school. As part of the NHES-99 protocol, a subsample (n=857) of high school students who reported participating in service activities was randomly selected to receive a more extensive interview about the types of services they performed. The information obtained from the youth included the number of hours spent doing service activities in the past year, whether the service was voluntary or required, and the type of service. 4 tables and 51 references