An experiment was carried out to evaluate the effects of adding phytase on nutrient digestibility in growing pigs. Three barrow pigs averaging 28.5$pm$3.1kg of body weight were allotted to three treatments by 3$ imes$3 latin square. Treatments included 1) com-soybean meal based-control diet and 2) and 3) control diet with phytase 500 and 1,000 unit. There were no effects of treatments on dry matter and nitrogen digestibility (P〉0.05). Ash, Ca and P digestibility in pigs fed diet with phytase were greater than those in pigs fed control diet(P〈0.05). An increased phosphorus intake was observed from pigs fed diet with treatments compared to that from pigs fed control diet. Pigs fed diet with adding phytase had improved P absorption compared to pigs fed control diet(P〈0.05). There was no significantly effect on fecal and urine excretion(P〈0.05). Ca intake was increased for pigs fed adding phytase compared to pigs fed control diet. No evident effect was observed on Ca fecal excretion among dietary treatments, however, urine excretion of pigs fed diet with treatments was decreased compared to pigs fed control diet. Cystine, isoleucine, tyrosine and phenylalanine digestibility of amino acid were greater for pigs fed diet with treatments than those for pigs fed control diet(P〈0.05). Asparagine, threonine, serine, methionine and leucine digestibility were improved for pigs fed with phytase 500 unit compared to pigs fed control diet. Lysine, histidine, arginine and other animo acids digestibility were higher for pigs fed diet with phytase than control diet, but there were no significant effects by the treatments(P〉0.05). In conclusion, the results of the experiments suggest that phytase supplementation in the diets could be a very beneficial strategy in environmental aspects.