For the evaluation of the effect of acute hypoglycemia on the auditory pathway, the changes of auditory brainstem-evoked response(ABR) were observed after administration of insulin(0.4ūkg) in guinea pigs. Two hours after administration of insulin, there was maximal threshold shift and prolongation of each wave latency in ABR with minimal blood glucose level. Although rapid recovery from these changes was observed in glucose administration group, it did not correspond with the change of blood glucose level. It was noted that the prolongation of both wave I and wave I-V interpeak latency contributed to the prolongation of wave V latency in ABR. These results suggest that both inner ear and brainstem auditory pathway might be affected by insulin-induced hypoglycemia.