Thirty-seven obese children 8 to 14 years of age were given a diet 115 kJ/kg of ideal weight for height and were distributed in two groups. One group was under normal ward conditions and the other underwent a physical exercise programme. Body weight, the percent of ideal weight referred to height, percent body weight, and absolute body fat were determined before and 15 days after both therapeutic regimes. The results revealed significant differences in the reduction of these parameters (p < 0.001). When comparing the two groups, only the reduction of percent body fat displayed a significant difference (p < 0.02), showing a greater reduction in those who had performed physical exercise.