The current experiment was conducted to determine the effect of dietary supplementation of Spirulina platinsis and organic selenium on productive and reproductive performance, egg quality, and blood traits of laying hen under heat stress conditions. A total of 90 Gimmizah developed local strain laying hen and 18 cocks (54 weeks of age) with an average initial weight 1724 g were used for three months during late production period. Birds were randomly distributed into three treatment groups with three replicates, each contained 10 hens and 2 cocks. The first treatment was fed the basal diet only without any supplementation and the other two treatments were fed the basal diet supplemented with Spirulina platinsis powder and seleno-methionine at levels (0.15 and 0.10 mg/kg diet), respectively. All treatment groups were exposed to chronic hot ambient temperature (38 °C±1; 55-65 % RH) for three successive days a week from 11.00 am until 15.00 pm. The results indicated that dietary Spirulina platinsis and organic selenium improved productive and reproductive performance, total antioxidant capacity, glutathione peroxidase, superoxide dismutase and immunoglobulins whereas decreased malondialdehyde level in blood, and can decrease the adverse effect of stress on laying hen under heat stress condition. It can be concluded that Spirulina platinsis and organic selenium supplementations can improve productive, reproductive performance, antioxidant and immunity status under heat stress conditions.