In a study of primary brain tumors 104 cases having satisfactory clinical, operative and histological proofs were analyzed by computerized tomography at Presbyterian Medical Center from May, 1982 to April 1985. The results were as follows: 1. The male to female of primary brain tumor was 54:46. The 2nd decade group(26%) was the most prevalent age group, followed by the 5th decade(16.3%), 1st decade(14.4%), 3rd decade(12.5%), 4th decade(11.5%), 6th decade(10.6%), 7th decade(8.7%) in that order. 3. The incidence of primary brain tumors was found to be: glioma 64 cases(61.6%)(among the GM, the most frequent 17 cases(16.3%), followed by meningioma 12 cases(11.5%), pituitary adenoma 10 cases(9.6%), craniopharyngioma 6 cases(5.8%), pinealoma and germinoma 3 cases(2.9%) respectively, and dermoid cyst 2 cases(1.9%) in that order. 4. The locations of the primary brain tumors were as follows: cb. hemisphere(49%) of these 24.5% in parietal region, 11.9% in temporal region, 9.7% in fronta region, 3.0% in occipital region; Juxtasella area(16.3%), cerebellar hemisphere(8.7%), Parapineal and intraventricle(7.7%) respectively, cerebello-pontine angle area(5.8%), vermis and 4th ventricular region(4.8%). 5. There were no remarkable differences in the findings of pre-and post-contrast CT scanning of primary brain tumors compared with others.