Sudden deafness is defined as an abrupt onset of sensorineural hearing loss which develops over a period of hours or a few days without definitive cause. The etiology, pathogenesis and treatment of sudden deafness have not been fully determined. Authors observed eighteen patients of sudden deafness admitted in Chonnam National University Hospital from July 1984 to July 1987. To evaluate the incidence and recovery, age, sex, affected side and recovery related to initial hearing loss, severe vertigo and tinnitus initial audiogram pattern as well as the time of initial visit were analyzed. The obtained results were as follows. 1) The incidence : 50%(9 patients) in 3rd decade, 55.56%(10 patients) in male, and 38.9%(7 patients) in left side. 2) Recovery evaluated in 24 cases : 8 cases(33.33%) of complete recovery, 4 cases(16.67%) partial recovery, 1 case(4.17%) slight recovery, and 11 cases(45.83%) no response. 3) In evaluation of prognosis. a) Patients treated within 2 weeks after onset showed better recovery(60%) than those treated 2 weeks or later(25%). b) Flat and ascending type hearing loss had a higher recovery(81.8%) than descending and profound loss(30.8%). c) Patients with mild hearing loss showed better recovery(100%) than those with severe and profound loss(44.44%). d) Patients with severe vertigo showed poorer recovery(16.67%) than those without severe vertigo(66.67%).