This study aimed to evaluate the effects of vitamin C supplementation in the drinking water on the ability to ameliorate heat stress in rabbits, through the evaluation of blood physiological and biochemical, and growth and reproductive performance of rabbits. The experiment was conducted in 2 rabbit groups: growing rabbits and reproductive rabbits. The first experiment: fifty local crossbred rabbits at 40-55 days of age (691.2±12.5g) were arranged in a completely randomized design with 5 treatments, 5 replications. Two rabbits including 1 male and 1 female were in one experimental unit (a cage). Five treatments were levels of vitamin C supplementation: 0, 250, 500, 750 and 1,000 mg/l in drinking water, respectively. The second experiment: 20 reproductive crossbred doe rabbits at the second litter of 8-8.5 months of age were also arranged in a completely randomized design with 5 treatments (corresponding to the levels of vitamin C supplementation as the first experiment), 4 replicates, 1 doe rabbit per experimental unit. The study results showed that the WBC, RBC and hemoglobin counts were improved in the first group, however, this difference was not significant (P>0.05). Contributing to enhancing the resistance and ability to absorb nutrients hence it could improve daily weight gain (DWG). Supplementation at 500 mg/liter/day and 750 mg/liter/day gave the best effect (P

Key words: Blood biochemical and physiology, heat stress, rabbits, vitamin C