This study was carried out to investigate the effect of amino acids complex and choline supplementation on the antioxidant enzyme activities and oxidative stability of Hanwoo (Korean cattle) beef. Fifteen months-old-Hanwoo steers were assigned into two groups and fed on a basal diets with or without amino acids complex (≥25% L-lysine monohydrochloride+≥8% DL- methionine)+choline (≥25% choline chloride) for 12 months. After slaughter, the M. longissimus from carcasses were stored at 4℃ for 7 days. Catalase, glutathione peroxidase and total superoxide dismutase activities were found to be unaffected by supplementation of amino acids+choline. After 2 days of storage, significant decline (p<0.05) in lipid oxidation (2-thiobarbituric acid reactive substances, TBARS) was observed when supplemented with amino acids+choline. However, supplementation of amino acids+choline maintained meat color as indicated by higher CIE L* (Lightness), a* (Redness), b* (Yellowness) and C* (Chroma) values during storage. It was therefore concluded that supplemental amino acids+choline could stabilize the lipid oxidation stability and meat color in Hanwoo beef.