This study was conducted to find the effect of in-class nutrition education and exercise program for obese adolescent boys in Taegu with the nutrition knowledge test before and after education program and anthropometric measurement. The subjects were consisted of a normal group (NG; n= 13) and an obese group (n=30). The obese group is divided into two groups; obese group A (OG-A; n=12), participated in a ten-week nutrition education only; and obese group B (OG-B; n=28), participated in a ten-week nutrition education and exercise program. The anthropometric data of the three groups were increased after the nutrition education program. However the obesity index(BMI, R hrer, WHR, Skinfold thickness) of OG-B were significantly decreased after the programs. The nutrition intake data were also changed after the nutrition education program. Especially the intake of carbohydrate was significantly decreased in OG-B from $421.5{pm}155.9g$ to $349.0{pm}41.0g$ (p<0.05) after the nutrition education program. It was noted that the intake of Ca was significantly decreased in all three groups after the nutrition education program. The mean score of the nutrition knowledge test also significantly increased from $13.7{pm}3.1$ to $17.8{pm}3.0$ after the nutrition education program. The result strongly suggested that nutrition education program should be successful if the obese adolescents and their parents especially mothers participated in the same class. In summary, nutrition education and exercise programs were effective on reducing obesity of obese adolescents. Nutrition knowledge of obese adolescent was significantly increased after nutrition education program.