This study was conducted to investigate the effect of dietary supplementation of phytase enzyme on growth performance and some blood parameters of Japanese quails. A total number of 200 one day old Japanese quail chicks with nearly similar initial average weight were used in this study. Chicks were randomly distributed into four experimental groups each of 50 birds. Chicks of the 1^st experimental group were fed basal diet and considered as control group. Chicks of the 2^nd, 3^rd and 4^th experimental groups were fed the basal diets supplemented withPHE at a levels of 25, 50 and 75 g/ton diet, respectively. Results obtained showed significant variations (p<0.05) in averages live body weight (LBW), body weight gain (BWG), growth rate (GR), feed intake (FI) and conversion (FC), mortality rate (MO), performance index (PI), absolute weight of carcass and giblets due to dietary phytase applied. The highest significant improvement in LBW, BWG, GR, FC, PI, carcass traits, REE and lower mortality rate were showed by quail chicks fed diet supplemented with phytase enzyme at a level of 50 and 75 g/ton diet, respectively, followed by those fed diet supplemented with 25 g phytase enzyme /ton when compared with control group. Chicks fed diet supplemented with 50 and 75 g phytase/ton diet , respectively significantly increased plasma total protein, globulin, calcium and inorganic phosphorus and decreased plasma ALT, creatinine, uric acid and plasma cholesterol compared with the other level of phytase and control group. It could be recommended to use phytase enzyme at a level of 50 and 75 g/ ton diet, respectively to improve the productive, metabolic performance and economical efficiency of Japanese quail.