This work was performed to investigate the effect of Spirulina platensis levels and vitamin E under heat stress on the performance, some physiological and blood biochemical constituents, antioxidant and immune responses traits of growing chickens. A total of 150 male Gimmizah local strain chicks (4 weeks of age) were randomly distributed among five treatment groups in battery brooder placed in a temperature-controlled room until 14 weeks of age. The first treatment was fed the basal diet only without any supplementation and kept in the first sector under optimum temperature 22-24oC and relative humidity (RH) 45-55 % (normal) used as negative control. Whereas, the other four treatments were kept in the last sector under chronic heat stress condition (38°C±1; 55-65 % RH) for three successive days a week from 11.00 am until 15.00 pm. The first heat stress group was fed the basal diet only without any supplementation and used as positive control (PC). Whereas in the other three treatments were fed the basal diet supplemented with Spirulina platensis at levels (0.5 and 1 g/kg diet) and vitamin E (75 mg/kg diet). The results indicated that different supplementations as Spirulina and VE decreased adverse effect of heat stress on growth performance and blood total protein, albumin, globulin, createinin, ALT, AST, total lipids, LDL, WBCs, RBCs, immunity of Chickens. In conclusion, addition of Spirulina platensis improved growth performance, immunity and can be decreased adverse effect stress on chickens under heat stress condition.