Sudden sensorineural hearing loss is not rare but its pathophysiology has not been fully determined and treatment is controversial at present. To evaluate prognostic factors and incidence, we analyzed 60 patients(male ; 28, female ; 32), treated with bed rest, steroid, vasodilator, plasma expander, from May 1980 to April 1989. Hearing loss was unilateral in 57 patients and bilateral in 3 patients. Recovery was complete in 23 patients(38%), partial in 9 patients(15%) and 6 patients(10%) had slight improvement but 22 patients(36%) had no improvement. 23 patients(38%) with dizziness and 31 patients(52%) with descending type audiogram had poor recovery. 51 patients(85%) being treated early(within 10 days after onset) had better prognosis. Hearing loss in lower frequency improved better than that in higher frequency. Other factors such as tinnitus, preceeding URI, age didn't affect recovery. Overall incidence rate was 0.11% among outpatients and was lower in winter than other seasons.