This study conducted to evaluate the effect of prebiotics (Fermacto), isoleucine and their combination on carcass characteristics and morphology of ileum during finisher period in broiler. A total 300 one-day-old mixed Ross broiler chicks were reared in same condition up to 21 day. Birds were distributed randomly into 4 treatments and 5 replicates. Control group was fed with the basal diet composed of corn-soya and wheat. In the experimental groups; either 0.1% prebiotic and 0.04% isoleucine or their combination was added. The experiment lasted from 22 to 42 days of broiler age. The results at the end of the experiment showed that prebiotic and isoleucine significantly (P<0.05) improved the efficiency of the villus height, width and the ratio of villus height to crypt depth and reduction of crypt depth, but it had no significant effect on traits such as dressing percentage, breast weight, abdominal fat weight and weight of bursa, however, the leg weight increased significantly in the group fed isoleucine and prebiotic. These results showed that the combination of prebiotic and isoleucine improved the leg weight and intestinal morphology in broiler.