Rabbits are widely used as laboratory animals for experimental surgery. Anesthesia of rabbits may present complications unless the method is easy to apply and safe to use. In present study, effects of different dosages of vitamin C on thiopental sodium induced anesthesia in 25 male New Zealand white rabbits were studied. In the animals that had not received vitamin C treatment before thiopental sodium induced general anesthesia, return mean time of front limb pedal, corneal and ear pinch reflexes were 6.40 ± 1.67, 6.60 ± 2.96 and 8.00 ± 2.58 minutes, respectively. Pre-treatment of rabbits with 30 and 240 mg kg-1 (IV) of vitamin C followed by thiopental sodium 20 mg kg-1 (IV) resulted in significant (P < 0.05) increase in front limb pedal reflex return mean time to 13.00 ± 2.24 and ear pinch to 11.60 ± 4.16 minutes, respectively. There was also significant (P < 0.05) decrease in the heart rate following induction of anesthesia in the animals pre-treated with 30 and 90 mg kg-1 (IV) vitamin C and no change in the animals pre-treated with 240 mg kg-1 (IV) vitamin C. Serum analysis indicated a significant (P < 0.05) increase in blood glucose. These results suggest that premedication of rabbits with vitamin C despite potentiating of thiopental sodium anesthesia in rabbits is not dose dependent.