Auditory brainstem responses were recorded by conventional scalp electrodes in 6 infants(1 month to 6 months of age). About 3 to 18 months after first examination longitudinal successive changes were studied by recording auditory brainstem response in those 6 infants. The latency of the major reponse component(wave V) and the interwave latency of wave I-V were progressively shortened postnatally to reach the adult value by 18 months of age. The latency of wave V at 60dB HL was progressively shortened, however, the latency of wave V at 30dB HL did not differ from the latency of wave V in adults.