The study evaluated the effectiveness of intervention for male adolescent smokers by making an assessment in terms of changes in food habits, nutrition knowledge, plasma catalase, superoxide dismutase(SOD), glutathione peroxidase peroxidase(GSH-px) activities and thiobarbituric acid reactive substance(TBARS) after Vit C supplementation and nutrition education. The subjects, male adolescent smokers, were assigned into four groups : Control group(19 students), education(Educ.) group(19 students), Vit C supplementation (suppl) group(19 students), and Educ. + Vit C suppl. group(19 students). The Educ. group and Educ. + Vit C suppl. group received nutrition education once a week for 2 weeks. The Vit C suppl. group Educ. + Vit C suppl. group received 500 mg ascorbic acid for 35 days. All data were collected before intervention and after intervention. Nutrition knowledge of those who received education increased, and the frequency of fruit and yellow-green vegetable consumption also increased. Plasma antioxidant enzyme activities were not different except for the SOD activity in the Educ. + Vit C suppl. group, which was significantly increased. The plasma ceruloplasmin level of groups that received Vit C supplementation was reduced more than any other groups, and the specific ceruloplasmin ferroxidase activity of groups that received Vit C supplementation was elevated more than other groups. These intervention programs had an impact on food habits, nutrition knowledge, plasma antioxidant enzyme activities, and plasma TBARS in male adolescent smokers. Various nutrition education programs must be implemented for adolescent smokers, and further studied are needed regarding sorts and amount of antioxidant nutrients and supplementation duration.