This study was conducted to determine the effect of elevated dietary amino acid levels in corn-soya diets on growth performance and carcass characteristics of commercial broilers. A total 200 broiler chicks (Cobb 400) were randomly assigned to four treatments: viz. T1 (control) was fed with standard diet as per BIS (1992) and the groups T2, T3 and T4 were fed with standard diet + 5, 10 and 20 % additional amino acids (DL-methionine, L-lysine and L-threonine) than BIS (1992) recommendation, respectively. The birds fed diet with 10% additional amino acids (T3) had higher (P<0.05) final body weight and overall gain in body weight than the control diet (T1) and 20% additional amino acids supplemented diet (T4), while comparable to the 5% additional amino acids supplemented group (T2). The feed intake was higher (P<0.05) in T3 group followed by T1 and T2 groups and lower in T4 group. The dressing percentage, weights of heart, spleen and gizzard were not affected by the additional supplementation of amino acids. However, liver weight was significantly higher in groups supplemented with 10 and 20% additional amino acids in broiler ration. Return over feed cost (Rs. / bird) was higher in T2 (48.81) and T3 (47.33) groups than T1 (43.32) and T4 (42.79) groups. It was concluded that 10% additional supplementation of amino acids (DL-methionine, L-lysine and L-threonine) to corn-soya diet resulted in improved final body weight, feed intake and return over feed cost in commercial broilers.