To elucidate the effects of an obesity control program on body composition and serum lipid levels, 31 obese elementary students (male: 25, female: 6) residing in the Gyeonggi area were evaluated and their body composition, serum total cholesterol, HDL-cholesterol, LDL-cholesterol and TG (triglyceride) were analyzed. The average age, height, weight and BMI (body mass index) were $11.52{pm}1.00;yrs$, $151.96{pm}8.04;cm$, $68.21{pm}9.03;kg$ and $29.40{pm}1.79;kg/m^2$ for the males, respectively, and $11.17{pm}1.17;yrs$, $147.83{pm}5.15;cm$, $65.05{pm}10.86;kg$ and $29.62{pm}3.24;kg/m^2$ for the females, respectively. There was a significant decrease in BMI for males (p<0.001) and females (p<0.05). There were also significant changes in all of the biochemical levels evaluated before and after the study. Specifically, the total cholesterol, LDL-cholesterol and TG level decreased after the obesity control program, while the HDL-cholesterol level increased after the program. These results indicate that obesity control programs do change the BMI, serum total cholesterol, HDL-cholesterol, LDL-cholesterol and TG levels in obese elementary students. Thus, obesity control programs are urgently needed to prevent degenerative disease and decrease obesity among children in elementary school.