This experiment was attemptel to observe possible effects of ether, halothane and methoxyflurane on the blood sugar level of the rabbit, 5, 15, 30 and 60 minutes after start of anesthesia with ether halothane and methoxyflurane by a non-rebreathing system. Comparision was made between preanesthetic and postanesthetic levels of blood sugar and the following results were obtained. In the ether anesthesia group, the blood sugar level 15 minutes after anesthesia was increased and decreased gradualley a anesthesia was progressed. In the halothane group, the blood sugar level was increased 5 minutes after anesthesia, and then decreased more rapidly than in other groups. Blood sugar levels 60 minutes after anesthesia had returned to preanesthetic levels in all groups. As the above result shows, blood sugar levels were revealed to have a tendency to increase during induction of anesthesia, and then returned gradually to the preanesthetic level during maintenence of anesthesia.