In Otolaryngologic field, sudden hearing loss is not rare, and it still remains as a medicosocial problem. Even with the abundant studies about sudden hearing loss, the pathophysiology has not been fully determined until now. And treatment is also controversial at present. Authors observed 137 patients with sudden hearing loss during a 8 year period(from Jan. 1980 to Jan. 1988) at our ENT department. Among them, only 27 patients(33 ears) were admitted under the impression of idiopathic sudden hearing loss. They were evaluated by clinical & statical analysis. The results were as follows : 1) Male : Female ratio was 17(63.0%) : 10(37.0%). Among 27 patients, unilateral involvement : bilateral involvement ratio was 21(74.8%) : 6(25.2%). Among 21 patients, Rt ear : Lt ear involvement ratio was 7(33.3%) : 14(66.7%). Common age group was 5th decade(7 patients, 26%). But there was no definite difference between common age group and other age groups. 2) The therapeutic results were 4 cases of complete recovery, 4 cases of partial recovery, 6 cases of slight recovery & 19 cases of no improvements. 3) History of upper respiratory infection was noted in 7 cases(21.2%). There was no intimate relationship between presence of preceding URI and recovery rate. 4) Patients who were treated within 14 days from onset showed better recovery(71.4%) than those treated 14 days or later(21.1%) 5) Vertigo was noted in 14 cases(42.4%). Patients without vertigo showed slightly better recovery rate(47.3%) than those with vertigo(35.7%). 6) Tinnitus was noted in 23 cases(69.7%). There was no intimate relationship between presence of tinnitus and recovery rate. 7) In this study, there was no intimate relationship between degree of initial hearing loss and recovery rate. 8) In this study, there was no intimate relationship between initial audiogram pattern and recovery rate.