The enforcement and its effect of weight control program including nutrition education, exercise and behavioral modification therapy during 20 weeks were studied in primary school obese children. The sample consisted of treatment group(n=19) and control group (n=23). To evaluate the effects of weight control program, treatment group took pretest and posttest for nutrition knowledge, attitude and food habits. Nutrient intakes, serum lipid levels and anthropometric values were also measured. After weight control program, body weight of treatment group significantly decreased from 47.0$pm$9.0kg to 45.9$pm$8.5kg(p<0.001), but than of control group increased from 47.8$pm$8.1kg to 49.0$pm$8.7kg (p$leq$0.05). Obesity index showed decline of 8.6% for treatment group and gain of 0.7% for control group. After self-control period, body weight and relate index in both groups were increased. For the nutrition knowledge test results, the posttest mean scores of treatment group showed the significant increase(p<0.001). For the attitude toward nutrition and food habit results, the posttest mean scores increased significantly (p<0.05, p<0.01). There was a decline of 28% in serum triglycerides, whereas serum total cholesterol increased 11% of baseline. These findings suggest that well-combined weight control program for obese children may result in a substantial loss of body weight during 14 weeks. In addition, these reuslts indicate that weight redution through weight control program can be a viable approach to help normalize serum lipids in obese children. Finally, these data suggest that it may be important to identify that affect weight loss and maintenance, and to examine how to manipulate these factors in weight control program.