Brainstem evoked response audiometry is a useful method for evaluating auditory thresholds in patients such as infants, adults unable to cooperate, unconscious patients, malingerer and is a useful diagnostic tool for localizing the sites of lesions of otoneurological diseases. This paper supports the reliability of BERA in evaluating auditory thresholds of children under three years of age. The results are as follows : A. Over three years of age 1) There was no significant difference between the pure tone threshold, click detection threshold, and auditory brainstem response threshold in the patients. B. Under three years of age 1) The normal hearing group were forty two and the hearing impaired group were one hundred and seven, and about 23.8 percent of the normal group visited with complaint of hard of hearing, while about 11.2 percent of hearing impaired group visited without any complaint of hearing impairment. 2) The incidence of the 4KHz ABR thresholds of hearing impaired group under three years of age are as follows : 61-105dB ; 59.9%, 41-60dB ; 5.2%, No Response ; 32.5%. 3) Twenty-three cases of 'A' form were observed at the 13-36 months of age, among which were revealed combined abnormalities of 11 cases. 4) The absolute latency of wave V decreased as age increased.