Recently developed TRAP assay(Total Radical-trapping Antioxidant Potential) is a new technique which enable effectively the measurement of total antioxidant status in the plasma. Researches using TRAP method have rarely been reported in Korea. Therefore, we investigated effects of various life-style and dietary factors on plasma TRAP level in Korean adult population. The subjects consisted of 161 health adult male(n=105) and female (n=56) aged 19-57. A self-administered questionnaire ascertained life-style factors including smoking habits, alcohol use, physical activity. Dietary factors were analyzed by 24 hour recall method. TRAP was determined spectrophotometrically in plasma at 734nm. Mean plasma TRAP concentrations were slightly higher in males (1.35$pm$0.02mM) and females(1.30$pm$0.02mM) without significance. There were significant correlations between plasma TRAP levels and life-style factors including exercise and smoking Plasma TRAP levels were affected more by exercise than by smoking. Moderate amount exerciser(exercise time $geq$30min/day) had significantly higher level of plasma TRAP levels in male smokers(1.33$pm$0.03mM) were significantly lower than those in male nonsmokers(1.39$pm$0.01mM, p<0.05), but the difference was not seen in female subjects. Intakes of vitamin C(r=0.288, p=0.007) or folate (r=0.258, p=0.016) were positively correlated with plasma TRAP levels in nonsmokers, but those relations were not seen in smokers. Dietary factors such as vegetables (r=0.288, p=0.007)or folate (r=0.258, p=0.016) were positively correlated with plasma TRAP levels in nonsmokers, but those relations were not seen in smokers. Dietary factors such as vegetables (r=0.277, p=0.009) and legumes(r=0.263, p=0.013) consumption were positively related to plasma TRAP concentrations also in nonsmokers only. Regular green tea drinkers showed significantly greater level of plasma TRAP than the non green tea drinkers(1.36$pm$0.01mM vs 1.30$pm$0.03mM, p<0.05). These results suggest that the regular exercise($geq$30min daily), nonsmoking, and consumption of vegetables, legumes and green tea would contribute to improving plasma TRAP levels in Korean adults.