The current study was conducted to examine the effects of different cage stocking densities and sex on performance and physiological changes of laying Japanese quail reared under hot climate region for a period of 11 weeks (10 to 21 weeks of age). A total number of 600 Japanese quails (400 females and 200 males) at 10 weeks old were randomly distributed in a randomized block design with 4 treatments (71, 59, 50 and 43 quail per cage) or (140, 170, 200 and 233 cm 2 / bird) respectively. Each treatment group was represented by 3 replicates. During the experimental period all birds received 16 hrs of light and 8 hrs of dark. Results indicated that quails kept at low stocking density (233cm 2 / bird) recorded significantly (P≤ 0.05) higher live body weight, egg production, egg mass, feed intake, protein and energy intakes compared with quails kept at other stocking densities. Further, egg weight was not significantly affected by the experimental treatments. However, feed conversion ratio and mortality rate were progressively reduced (P≤ 0.05) with decreasing stocking density. There were significant reductions in plasma total protein fractions by lowering stocking density. Whereas, a significant increase in total lipids, cholesterol, ALT, plasma total calcium and phosphorous with increasing stocking density. While, insignificant differences were observed for HDL, LDL and AST. The results clearly indicated that decreasing stocking density was significantly (P≤ 0.05) decreased corticosterone level. While, IGg increased significantly (P≤ 0.05) due to decreasing stocking density, thus leading to increased susceptibility to resistance of infections. Other physiological traits (i.e., respiration rate, cloacal temperature, skin temperature and heart pulse rate) recorded higher values for quails kept at high stocking density (140cm 2 / bird) compared with those stocked at low stocking densities. On the other hands, sex had no effect on these traits. Traits of egg quality showed insignificant differences for the most, except for yolk index, shell thickness, yolk color and eggs with blood or meat spots. Also, insignificant differences were observed for all carcass characteristics except for live body weight, blood weight and carcass weight percentages. In conclusion based on the obtained results it could be concluded that egg production percentage, egg mass and immunological response improved as the cage space per quail increased. Therefore, it can be recommended that in order to minimize physiological stress in the cages of laying Japanese quail should raised at a density of 233 cm 2 /bird to exhibited superior performance and lowering mortality rate.