In order to assess the hearing impairment in patients with diabetes mellitus, the authors have performed the clinical observation in accordance with audiometric test and clinical findings of 42 cases(male 16 ; female 26) who were diagnosed of diabetes mellitus in Kang Nam St. Mary's hospital from March to June, 1984. The results obtained were as follows : 1) The over-all incidence of hearing loss was 38%. 2) The type of hearing loss was bilateral, sensorineural type at high frequency range. 3) The site of lesion was thought to be spiral ganglion and organ of Corti. 4) The incidence of hearing impairment is higher in older age group. 5) Hearing impairment has not related to duration of disease but blood sugar level. 6) Problems related to hearing impairment in diabetes mellitus have complexity.