The purpose of the present study was to determine the effect of a 12-week training program on the motor performance of 6- to 8-year-old prepubertal boys (n = 14). Each subject participated in a 40-min session twice a week, which included three sets of upper body strength exercises (1 to 15 repetitions/set), unregimented lower body strength exercises, coordination, balance, and martial arts skills. The control group included 15 prepubertal boys in the same age range. All subjects were pre- and posttested on 20-s sit-ups, seated ball put, standing broad jump, sit-and-reach flexibility, 6 × 4-m shuttle run, and a coordination task. The experimental group improved significantly (p < .05) more than the control group in the sit-ups and in the long jump. Both groups improved (p < .05) in the coordination task. No significant changes were observed in body weight, seated ball put, flexibility, and shuttle run. A twice-weekly training program seems to improve performance in selected motor tasks in 6- to 8-year-old boys.