This experiment was conducted to investigate the effect of microbial phytase supplementation on broilers performance, nutrient digestibility, carcass cuts and body status of Ca and P. A total of 200 day-old Cobb-500 chicks were used in the experiment. Birds were partitioned into five experimental groups of 40 birds. Each treatment was composed of 4 replicates with 10 birds in each. The control group was fed a commercial starter and finisher diet. The second treatment group was fed a phosphorus deficient diet, while the third, fourth and fifth treatments groups were fed a phosphorus deficient diets plus the microbial phytase. Phytase enzyme was incorporated at levels 1000, 2000 and 3000 PU/kg feed for the last three treatments, respectively. In the last week of experiment, four birds from each replicate were used in metabolic trial. However, at time of termination of the experiment, the same birds were killed for carcass cuts and tibia ash content investigations. Results of the experiment showed that the addition of phytase enzyme to P- deficient diets significantly improved (P<0.5) broilers performance. However, feed intake, feed conversion ratio and tibia minerals were significantly increased (P<0.05) in birds fed P- deficient diets supplemented with phytase. Phytase supplementation had no significant effect on carcass cuts and dressing percent compared to birds fed the low P diets. Also, results of this investigation showed that phytase enzyme increased (P<0.05) the digestibility of dry matter, crude protein and ash.