The purpose of this study was to find out the effects of aerobic training plus diet on blood lipids and apolipoproteins (Apo) in obese children. Sixteen healthy obese boys (ages 10.9; body mass index (BMI) $geq$95th percentiles for age and sex) participated in this study. The aerobic training program consisted of 40 minutes hiking on a mountain, 60 minute of basketball and football dribbling at an intensity of 60-70% of HRmax, and was performed 5 days a week for 9 weeks. The diet prescription was 2,100 kal/day according to the recommended dietary allowance for 10-12 year old Koreans. All subjects stayed in a training camp for 9 weeks. The results of this study were as follows; Blood lipid profiles including total cholesterol (TC), triglyceride (TG) high density lipoprotein cholesterol (HDL-C) and TC/HDL-C ratio were significantly improved after the 9 week program, but there was no significant change in low density lipoprotein (LDL-C). Apolipoprotein profiles, Apo AI, AII, B, CII and CⅢ were all significantly decreased after the 9 week program, but there were no significant difference in Apo AI/AII ratio and Apo B/AI ratio. These results indicate that aerobic training together with a healthy diet can induce positive changes on blood lipid profiles, Apo AII, B and CII in obese children.