This experiment was conducted to investigate the effects of phytase, on growth performance, carcass characteristics and some biochemical parameters of Japanese quail fed on low phosphorus diet. Japanese quail were divided into 5 equal groups, each group subdivided into 2 subgroup. One of them contain 16 males while the other contain 16 females. Japanese quail supplemented with five diets in both Males and females. First group (Positive control) fed on diet contain recommended level of available phosphorus N.R.C. (1994), second group (negative control) fed on diet contain 2/3 recommended level of  available phosphorus while the other three groups fed on negative control diet supplemented with (300,600 and 900 phytase enzyme unit FTU/Kg), respectively. growth performance results showed that body weight gain of negative control group significantly lowered relative to other groups while Feed conversion ratio of the adequate phosphorus groups or of the low phosphorus groups supplemented with phytasesignificantly better than the negative control groups in both  males and females. The data interested in carcass characteristics showed that dressing percentage. breast and thigh muscles were improved in all dietary treatments in both males and females compared with negative control and significantly increased in groups fed on diet supplemented with (600 &900 phytase enzyme unit FTU/Kg when compared with the positive control in case of males However leg muscle increased significantly in case of female (900 phytase enzyme unit FTU/Kg) when compared with the positive control. The present data revealed that serum globulin significantly increased in male group fedlow phosphorus diet supplemented with 900 phytase relative to other male groups, the serum phosphorus of female groupfedlow phosphorus diet supplemented with 900 phytase showed significantly higher relative to other female groups.