1. INTRODUCTIONFeed cost represents about 60-70% of the total costs of poultry production with three fourths of this cost being allotted to maintenance needs and the remainder for productive purpose. Accordingly, many attempts have been undertaken to reduce the cost of feeds and improve feed conversion efficiency by supplementing diets with enzyme preparation.The major ingredients used in poultry feeds are of plant origin. About two –thirds of the phosphorus (P) in these feedstuffs is present as phytate P, which is poorly utilized by poultry. The inability of poultry to utilize phytate P causes economical and environmental problems. The large amount of P in animal waste is creating environmental problems in many parts of the world especially where large concentrations of domestic animals are reared.Another aspect of this problem is supplementing poultry diets with expensive inorganic source of phosphorus for animal. Thus any attempt to improve the utilization of phytate P in Japanese quail chickens could reduce feed costs and P pollution.Sebastian et al. (1998) discussed the effect of phytate molecule on protein and energy utilization and its inhibitory effects on proteolytic and energetic enzymes such as pepsin, trypsin and α-amylase and concluded that Phytase improved protein and energy utilization of chick’s diets.Lyons and Jaceques, (1987) studied the effect of low and high-energy diets with the addition of enzyme on the berformance of broiler chicks and found that response was greater on the low energy diet.Phytase supplementation to a low Apparent metabolizable energy (AME) wheat based diet for broiler improved AME by 5.3% and nitrogen digestibility by 3.2% (Ravindran, 1999), as well as the utilization of N, P, Ca and Zn (Zanini and Sazzad, 1999).Therefore, the aim of the present study was to investigate the effect of supplemnting different levels of phytase in the diet of Japanese quail, differin energy level and its effect on the performance and efficiency of feed utilization and digestibility as well as some carcass traits.