Present experiments were undertaken for the purpose of clarifying the effect of repeated halothane anesthesia on the liver and kidney function. Nine mongrel dogs were divided into three groups. The group one dogs were anesthesized once(control group) and the other two groups twice and trice respectively on 10th day of previous anesthesia experimental groups. Hematological examinations and blood chemical assays were undertaken during the period from one hour to 10 days after the anesthesia. From these experiments fellowing results were obtained; 1. No significant changes of erythrocyte count were recognized in both the control and experimental groups after the halothane anesthesia. 2. The total leukocyte counts of experimental groups showed significant decrease on one hour and subsequent increases after the anesthesia. 3. No significant changes were observed in SGOT, SGPT, ALP, BUN and serum glucose values in both the control and experimental groups. 4. The total serum protein values showed a tendency to decrease on the first hour of halothane anesthesia in both the control and experimental groups. From these results it may be concluded that the repeated halothane anesthesia done 10th day of previous anesthesia do not affect the liver and kidney function in dogs.