There are few physical activity (PA) interventions in higher education, and they have been only minimally effective. Objective: To determine if a course-based, peer education intervention was associated with increases in PA and physical fitness. Participants: Participants were 178 students enrolled in a personal health class during the 2007-2008 academic year. Methods: A quasi-experimental design was used to assess the effect of the intervention. Repeated measures analysis of covariance was employed to test the impact of the intervention on students' PA, body composition, waist-to-hip ratio, cardiovascular fitness, flexibility, and muscular strength. Results: Women in the treatment group classified as "Inactive" at baseline increased PA, whereas "Inactive" control women had reductions in PA. Women in the treatment group who were "Active" at baseline reduced their waist-to-hip ratio and increased flexibility. There were no differences by treatment group among men. Conclusions: The intervention was effective in improving PA and physical fitness among college women. (Contains 4 tables.)