The cardiovascular and respiratory effects of pentobarbital, ketamine, chloralose and urethane were studied in decerebrate rats. All the anesthetics reduced blood pressure and heart rate. Pentobarbital, chloralose and ketamine, but not urethane, reduced respiratory rate. None of these agents had a significant effect on tidal volume. All these anesthetics significantly attenuated the carotid occlusion, tilt and sodium cyanide chemo-receptor response. These results suggest that the decerebrate rat may be a more suitable preparation, compared to the anesthetized one, for studying cardiovascular and respiratory responses in this species.