The brainstem evoked reponses of the electrical stimulation on the cochlear nerve were compared with those of the electrical stimulation in the scala tympani described elsewhere, and with those of the acoustic stimulation as a control group, in 5 cats. The posterior fossa approach technique was used to expose the cochlear nerve. The acoustic stimuli were 2, 4, 6 KHz logon, and the electrical stimuli were the electrical current produced by the sound processor with the acoustic stimuli. 1) The wave pattern in the electrical stimulation on the cochlear nerve was similary to that in the electrical stimulation in the scala tympani. But these wave patterns were simpler than the wave pattern in the acoustic stimulation, and only the peak of wave V was identfied. 2) With respect to wave V latency, there was no difference in 3 frequencies(2, 4, 6 KHz) in the electrical stimulation on the cochlear nerve. So there was no frequency specificity in the electrical stimulation on the cochlear nerve as in the electrical stimulation in the scala tympani. 3) The average wave V latency in the electrical stimulation on the cochlear nerve was shorter than that in the electrical stimulation in the scala tympani, by about 0.7msec.