Diabetes Mellitus(D.M.) has long been known as a multisystemic disorder. But there have been various conflicting report regarding the incidence of hearing impairment in diabetes. An audiological study has performed in 110 diabetic patients(male 53, female 57). The patients were categorized into groups according to age, duration of disease, complication and control of diabetes. These observations were compared with those from a control group(Incidence of presbycusis) using appropriate statistical methods. The results were as follows ; 1) In all diabetic patients, the incidence of hearing loss over 26dB in speech range(0.5~2KHz) was 36.4% and in high frequency range(3~6KHz) was 68.2%. 2) Patients with D.M. over 50 years age showed a significant high frequency hearing loss as compared to control population(P<0.05) but no significant difference in speech range. 3) Bilateral sensorineural hearing loss(SNHL) was noted in 90.6%, and the most common audiogram pattern was abrupt descending pattern, 67.6%. 4) The site of lesion was cochlea in 48% and retrocochlea in 52%. 5) Patients with complicated diabetes had significant hearing loss as compared to those with uncomplicated diabetes(P<0.05). 6) When the incidence of hearing impairment was compared with the duration of the disease, there was significant difference between under and over 4 years duration(P<0.05), and between under and over 15 years(P<0.05). 7) In conclusion, D.M. causes high frequency hearing impairment and the possibility of hearing impairment is increased when the duration is over 4 years and diabetes is complicated.