In order to determine the effects of beta-glucanase and virginiamycin in barley based broiler diets on performance and digestibility of nutrients, an experiment was conducted using 720 Ross broiler chicks. Barley was substituted for corn at levels of 0, 25, 50 and 75%. Antibiotic and beta-glucanase were used at levels of 30 grams and 1000 grams of diet respectively. Each experimental diet was fed to three replicates of birds (15 birds per replicate). Experimental period lasted 6 weeks. The experiment was carried out in a completely randomized design in a 4×2×2 factorial arrangement. Weight gain, feed consumption, and feed conversion ratio were determined at the end of each period of experiment. In addition, the digestibility of nutrients and digestible energy (DE) of whole diets were measured by ileal collection method. Increasing dietary barley reduced body weight gain significantly (p 0.05). Enzyme and antibiotic supplementation improved body weight gain significantly (p 0.05). At the end of the experiment the feed intake was lowest for diet contained 75% barley, the highest feed intake belonged to diet contained 50% barley and enzyme (p 0.05). Feed conversation ratio was increased significantly by increasing dietary barley (p 0.05). FCR was improved by antibiotic and enzyme supplementation (p 0.05). Antibiotics supplementation had a significant effect on intestine weight. Increasing dietary barley reduced abdominal fat (p 0.05). No significant difference was seen by increasing barley level on carcass weight, however, due to antibiotic consumption a considerable increase was seen on the carcass weight (p 0.05). It seems that by increasing dietary barley, protein digestibility was decreased (p 0.05).Enzyme caused an increase in protein digestibility (p 0.05). Results showed that, digestibility of fat increased by using enzyme (p 0.05). Increasing barley reduced DE (p 0.05), but, using enzyme or antibiotic had significant difference on the DE (p 0.05). Overall results showed that addition of enzyme to the diets contained 50 and 75% barley had significant effects compared with another levels of barley.Enzyme and virginiamycin together in rations with high barley percentage had better effects on broilers performance. Finally, results showed that, barley is a good and appropriate substitution for corn when enzyme and virginiamycin were used.