|This study was conducted to evaluate the effects of a composite feed additive (CFA) consisting of vitamin C, vitamin E, selenium, and choline on growth performance, carcass characteristics, and meat properties of Hanwoo steers. Twenty-two late fattening steers were randomly assigned to one of two dietary groups, control (commercial concentrate + rice straw) and treatment (commercial concentrate + rice straw + 50 g of CFA). Average daily gain (ADG) was 4.0% higher in treatment than that in control; however, there was no statistically significant difference. The supplementation of CFA had no effect on overall yield or quality traits of carcass. CFA had no effect on chemical composition, water holding capacity, shear force, cooking loss, or myoglobin values in longissimus muscle; however, the content of α-tocopherol was increased by supplementation of CFA (p < 0.01). The contents of α-linolenic acid and n-3 fatty acids were higher in treatment group than in control (p < 0.01). The ratio of n-6/n-3 fatty acids was decreased by supplementation of CFA (p < 0.01). The supplementation of CFA had no effect on pH or thiobarbituric acid reactive substances (TBARS) values in longissimus muscle (raw); however, TBARS (cooked) values were lower in treatment group than in control during refrigerated storage (p < 0.01). Thus, the results indicate that the supplementation of CFA (vitamin C + vitamin E + selenium + choline) had some positive effects on the increase in α-tocopherol and n-3 fatty in longissimus muscle, without any negative effect on growth performance or carcass characteristics of late fattening Hanwoo steers.