The purpose of this study was to examine the effects of medicine ball training on the fitness performance of high-school physical education students. Sixty-nine high-school students participated in a 6-week medicine training program during the first 10 to 15 minutes of each physical education class. A group of 49 students who participated in physical education lessons but not medicine ball training served as controls. Performance on the shuttle run, long jump, sit and reach flexibility, abdominal curl, medicine ball push-up, and medicine ball seated toss was assessed at baseline and post-training. Students who participated in the medicine ball training program made significantly greater gains on all fitness tests as compared to the control group. These data suggest that medicine ball training can enhance selected measures of speed, agility, power and muscular endurance when incorporated into a high school physical education class. (Contains 2 tables.)