It has been reported that cigarette smoking increases free radical generation, which can also increase lipid peroxides and deplete antioxidants. The purpose of this study was to determine whether cigarette smoking and other lifestyle choices may affect serum lipid peroxide concentrations, serum antioxidant concentrations such as tocopherol and vitamin C, and serum antioxidant enzyme activity such as glutathione peroxidase and superoxide dismutase. Dietary intakes were assessed by 24-hour recall and survey questionnaires from 48 male non-smokers and 52 male smokers. Overnight fasting blood was collected and measured for individual antioxidant status. The daily vitamin C intakes of smokers tended to be lower than those of non-smokers, and the intakes of both groups were under the Recommended Daily Allowance (RDA). Vitamin E intake was sufficient for smokers and non-smokers. Serum lipid peroxide concentrations were no difference among all subjects. The serum $alpha$-tocopherol concentrations of all subjects were in a normal range, and they were highest in mild smokers (p<0.05). Mean serum vitamin C levels were lowest in heavy smokers (p<0.05). The activities of serum glutathione peroxidase and superoxide dismutase were not significantly different in smokes and non-smokers. In conclusion, smoking did not increase oxidative stress in heathy young men. However, it is desirable for heavy smokers to consume more vitamin C than the RDA sine their serum vitamin C concentrations are relatively low.