Abstract: Three hundred and sixty one-day-old chicks (Arian) were used in a completely randomized design with 6 treatments and 4 replicates for each treatment. The experimental treatments were included: corn-soybean diet as control, 20% hulled barley and 20% hull-less barley with and without beta-glucanase enzyme. Body weights, feed intake and feed conversion were determined weekly. At 49 day 4 chicks were chosen randomly from each pen and killed to determine carcass and organs weight. The ME values of hulled and hull-less barley with and without enzyme were determined with adult roosters. The AMEn value obtained with hull-less barley significantly (p<0.05) was higher than hulled barley and the TMEn and AMEn values of hulled barley were increased 2.1 and 1.7% due to enzyme supplementation. There were no significant different in feed intake between chicks that fed with hulled or hull-less barley and control group in all ages. Body weight gain in 7 to 21 day were higher significantly (p<0.05) in broiler chickens that fed with corn-soybean diet and hull-less barley diet with enzyme supplementation. Enzyme supplementation improved feed conversion ratio at 7 to 49 day yin birds fed with barley, especially in hull-less barley diets. Abdominal fat pad, liver, pancreas and gizzard weight as a percentage of carcass weight were not affected significantly by treatments, but in all cases use of enzyme improved these organs weight. Birds that fed with barley based diets, especially hulled barley, had elevated intestinal weight.