All 25 patients surgically proven acoustic neurinoma was analysed clinically, radiographically at SeveranceHospital of Yonsei Univ. The patients not proved surgically inspite of clinical diagnosis of acoustic neurinomawas excluded from this study. The results are summarized as follows; The clinical findings are: 1. The incidenceof tumor in female was twice more frequent than in male and the range of age was 20-50 years peak of age at onsetof symtom. 2. The clinical symtoms were variable from unilateral hearing impairment of loss (100%), headache(84%)to tinnitus(60%) in order of freuquency. 3. The tumor growth in the left cerebellopontine angle was twice morethan in the right side with the ratio of 16:8. However in one case bilateral simultaneous growth of acousticneurinnoma was noted. The radiological findings are; The best radiographic method to study the shape and size ofinternal acoustic canal to demonstrated erosion or destruction of petrous pyramids was considered to be straightfrontal view and tomography of the skull in our series. 1. The shape of internal acoustic canal in tumors werestraight (in 2 cases), bulbous(in 12 cases), and flared (in 11 ases). Particularly there was erosion ordestruction of petrous bone in all of the flared cases of canal. 2. The acoustic meatal erosion was mainlysuprameatal in 14 cases 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 0-2mmmeasurement, remainder was more than 2mm. Hence the variation in greater than 1mm in between both sides of canalin same patient should be regarded as abnormal as of acoustic neurinoma. 4. The carotid angiogram showshydrocephalic 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 findings. 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 our series.