The present study was carried out to compare xylazine(2.2mg/kg, IV), xylazine/acepromazine(1.1mg/kg. IV : 0.2mg/kg, IV) and xylazine/diazepam(1.1mg/kg, IV :1.0mg/kg, IV) anesthesia, to determine useful method out of three kinds of anesthesia and tr evaluate this selected method at hypovolemic state. In xylazine, kylazine/acepromazine and kylazine/diazepam anesthesia, the heart rate was increases after administration of atropine until 10minutes after administration of anesthetics and then decreased gradually in all types of anesthesia. The respiratory rate was decreased after administration of anesthetics in all types of anesthesia. The body temperature was rarely changed in xyiazine/acepromazine and xylazine/diazepam anesthesia, but decreased continuously in xylazine anesthesia. In xylazine and kylazine/acepromazine anesthesia the pedal and corneal reflex were not disappeared completely, but reactions to pin pricking were disappeared. In xylazine/diazepam anesthesia their reflex and reactions were disappeared together. The time from head-up to standing was shortest(32.00min) in kylazine/diazepam anesthesia in comparision with xylazine and kylazine/acepromazine anesthesia. In xylazine/diazepam anesthesia, the heart rates in hypovolemic dogs were decreased soon after administration of anesthetics but recovered immediately. The changes in systolic and diastolic blood pressure in hypovolemic dogs revealed similar trends to their changes in normal dogs after administration of anesthetics. It is considered that rylazine/diazepam anesthesia is one of the useful anesthetic methods in healthy dogs and also in hypovolemic dogs.