A total of 180 unsexed 1-day old IR  broiler chicks were randomly distributed into 6 treatments  of  3 replicates each (10 birds each) in experiment for 5 weeks of age.  A factorial design (3×2) was used in which there were three levels of multienzymes, optizyme (0, 250, 500 mg/kg diet) and two levels of phytase enzyme (0, 1500 FTU/kg diet). The results showed that broiler chicks fed on either 250 or 500 mg/kg diet of optizyme alone or plus 1500 FTU/kg diet had significantly improved body weight gain (BWG) compared to control group. Tibia ash and phosphorous percentages were increased significantly (P<0.05) in broilers fed diets contained 250 mg/kg diet optizyme. Phosphorus retention efficiency percentages were increased significantly (P<0.05) in broilers fed diets contained 250 mg/kg diet optizyme alone or 250 mg/kg diet optizyme plus 1500 FTU/kg diet phytase. It could be concluded that the level of 250 or 500 mg / kg diet optizyme and 1500 FTU/kg diet phytase is effective for increasing absorption and bioavailability of phosphorus, which could decrease excretion of phosphorous and, therefore, environmental pollution. In addition, feeding broilers with these treated feeds might improve body weight gain.