This study was done to compare the effects of managing obesity using a behavior modification program and an aerobic exercise in adolescent girls. Thirty three subjects were selected from one girls' middle school located in Seoul. Seventeen girls participated in the behavior modification program by joining 60 ?90 minute group sessions weekly. The aerobic exercise program was given to 16 girls three times per week for 60 minutes each. These iter-ventions continued for eight weeks from October 17 to December 10,1995. The data were obtained before and after the interventions by measuring degree of obesity, body weight, blood pressure, serum lipid, %body fat, and waist to hip ratio (WHR). Data ware analysed by using paired t-test. The results are as follows. 1. Subjects in both the behavior modification and the aerobic exercise groups showed significant decresc in the degree of obesity, body weight, di-astolic blood pressure, total cholesterol, low density lipoprotein, %body fat and fat mass after the 8-week interventions. 2. Systolic bood pressure, high density lipoprotein cholesterol and waist to hip ratio were significantly decreased after the 8-week intervention in the behavior modification program group while triglyceride was significantly decreased after the 8-week intervention in the aerobic exercise program group. These findings indicate that both behavior modification and aerobic exercise programs are good strategies for managing obesity among adolescent girls.