The effects of alterations of dose of xylaznie (X) and Zoltil$circledR$ (TZ) on canine anesthesia were examined. Experimental groups were divided into three (Group 1: X 1.1 mg/kg and TZ 10 mg/kg, Group 2: X 1.65 mg/kg and TZ 7.5 mg/kg, Group 3: X 2.2 mg/kg and TZ 5 mg/kg), and each had 5 dogs. A femoral artery was catheterized for measurement of blood pressure, and baseline value was measured. The dogs were sedated with xylazine intramuscularly, then after 10 minutes TZ were injected intravenously. Mean arterial blood pressures (MAP), duration of analgesia, mean arousal time (MAT) and mean walking time (MWT) after TZ injection were measured, and the depth of analgesia and the quality of recovery were scored. The values of MAP were recorded from the time of pre-xylazine injection to arousal. Duration of analgesia and was assessed by tail clamping test, and which were done at 10 minutes intervals after TZ injection. The decreases of MAP from 40 minutes after TZ injection were significant (p<0.05). In group 2, MAP at 20 minutes, and from 40 minutes to arousal were significantly decreased (p<0.05). In group 3, MAP were significantly decreased from 40 minutes. MAT were 62.2$pm$9.2 minutes in group 1, 60.2$pm$7.5 minutes in group 2, and 71.0$pm$6.9 minutes in group 3. MAT in group 3 was significantly increased compared with group 2 (p<0.05), and the differences of MWT among each groups were not significant (p>0.05). The scores of quality of recovery were significantly lowered in group 3 compared with group 1 or group 2, which means the side effects of recovery were less occurred. Thus, it was considered that the combination X 2.2 mg/kg IM and TZ 5 mg/kg IV is more effective to surgical procedures and to prevent long and rough recovery of Zoletil anesthesia.