This study was carried out to investigate the effect of amino acids complex and choline supplementation onthe antioxidant enzyme activities and oxidative stability of Hanwoo (Korean cattle) beef. Fifteenmonths-old-Hanwoo steers were assigned into two groups and fed on a basal diets with or without aminoacids complex (≥25% L-lysine monohydrochloride+≥8% DL-methionine)+choline (≥25% choline chloride) for12 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 bysupplementation 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 concludedthat supplemental amino acids+choline could stabilize the lipid oxidation stability and meat color in Hanwoobeef.