Children with congenital heart defects often demonstrate a reduced capacity for exercise, even after surgical intervention. Forty subjects, with various heart defects, completed a 5-year study to evaluate the impact of a postoperative training program on their physical exercise capacity. All of the patients were significantly less active than their peers prior to the surgical intervention. Subjects who completed a simple, home exercise program during the first 3 postoperative months achieved a normal level of physical fitness. These benefits were maintained up to 5-years postoperatively without further intervention. Children who did not receive a postoperative training program remained significantly below their healthy peers. Therefore, a simple exercise training program, conducted early in the postoperative period would appear essential to the achievement of appropriate levels of physical activity for children with congenital heart defects.