A total of 210 twenty-day-old broiler chicks were used in this programme to investigate the performance, feed intake, digestibility and visceral organ mass of broiler chicks fed with high level of olive pulp supplemented with two antibiotics: streptomycin and tylosin. The two antibiotics were added to supply 150 mg/kg of the active ingredient. Chicks which consumed the medicated dietshad more (p,0.05) gain compared to chicks which consumed the basal diet. However, streptomycin caused more (p,0.05) gain compared to tylosin. Antibiotics had no effect on feed intake. The chicks that consumed the antibiotics had heavier (p0.05) weights of edible, inedible organs and small intestine but lower weights of large intestine and cecum. The digestibility of dry matter, crude protein and nitrogen free extract increased (p0.05) in chicks fed with the medicated diets compared to the chicks fed with the basal diet. It is concluded that antibiotic supplementation had a positive effect on chick's performance and digestibility.