The effects of ascorbic acid on the performance and some blood parameters of Japanese quails reared under hot conditions were investigated. Three hundred Japanese quails, 7 days of age, were randomly divided into one control and two experimental groups, comprising five replicates of 20 birds each. Ascorbic acid (500 and 1000 mg/kg) was given to the experimental groups. The body weight gain increased significantly (P < 0.05) in the group given 500 mg/kg of ascorbic acid until the fourth week. Feed consumption also increased (P < 0.05), depending on the quantity of ascorbic acid supplementation until the fourth week. However, ascorbic acid did not affect the concentrations of blood pH, PCO2, sodium (Na), potassium (K), hematocrit (PCV), bicarbonate (HCO3), or hemoglobin (Hb). In conclusion, 500 mg/kg of ascorbic acid may be added to the quail diet to prevent heat stress until the fourth week.