Objective Spirulina has been recognized formerly as a filamentous spiral-shaped blue- green algae or more recently as a genus of photosynthetic bacteria (Arthrospira). This microorganism is considered as a rich source of essential nutrients for human and animals. The present study was conducted to determine potential application of Spirulina for heat- exposed broilers. Methods Two hundred and fifty Cobb 500 chicks with male to female in equal ratio with average initial weight of 615.6 g at 17 days of age were divided into 5 treatments with 5 replicates of 10 chicks. Treatment groups were as follows: positive and negative controls with 0% Spirulina supplement and three Spirulina receiving groups with 5 g/kg (0.5%), 10 g/kg (1%) and 20 g/kg (2%) supplementation. Spirulina receiving groups as well as positive control were exposed to high ambient temperature for 6 h/d at 36°C from days 38 to 44. Biochemical variables were measured in serum samples at days 35, 38, 42 and 45 of broiler chickens age. Results The results showed that supplementation of the diet with Spirulina decreased concentration of stress hormone and some serum lipid parameters while enhanced humoral immunity response and elevated antioxidant status whereas didn't meaningfully affect performance characteristics. Nevertheless, feed conversion ratio was numerically improved in broilers fed with 1% Spirulina under high ambient temperature. Conclusion Overall, the present study suggests that alleviation of biochemical adverse impacts due to high ambient temperature in broiler chickens can be approached through supplementation of the diet with Spirulina platensis.