All 25 patients surgically proven acoustic neurinoma was analysed clinically, radiographically at Severance Hospital of Yonsei Univ. The patients not proved surgically inspite of clinical diagnosis of acoustic neurinoma was excluded from this study. The results are summarized as follows; The clinical findings are: 1. The incidence of tumor in female was tiwce more frequent than in male and the range of age was 20-50 years peak of age at onset of symtom. 2. the clinical symtoms were variable from unilateral hearing impairment or loss (100%), headache (84%) to tinnitus (60%) in order of frequency. 3. The tumor growth in the left cerebellopontine angle was twice more than in the right side with the ratio of 16:8. However in one case bilateral simultaneous growth of acoustic neurinoma was noted. The raidological findings are: The best radiographic method to study the shape and size of internal acoustic canal to demonstrate erosion or destruction of petrous pyramids was considered o be straight frontal view and tomography of the skull in our series. 1. The shape of internal acoustic canal in tumors were straight (in 2 cases), bulbous (in 12 cases), and flared (in 11 cases). Particularly there was erosion or destruction of petrous bone in all of the flared cases of canal. 2. The acoustic meatal erosion was mainly suprameatal in 14 case of 17 which was noted definite erosion radiographically. 3. The difference of height (vertical diameter) of both side of acoustic canal were follows; 6 cases among 25 was in the range of 0-2mm measurement, remainder was more than 2mm. Hence the variation in greater than 1mm in between both sides of canal in same patient should be regarded as abnormal as of acoustic neurinoma. 4. The carotid angiogram shows hydrocephalic pattern in 12 cases among 17. 5. In the vertebral angiogram of 8 cases, anterolateral displacement of basilar artery(in 6 cases), the upward displacement of superior cerebellar artery (in 4 cases) was common findi gs. In one case demonstrated elevated superior petrosal vein against petrous bone which is claim to be more diagnostic value in acoustic neurinoma, was gained less result in our series.