It is recognized that the differential diagnosis between an epidural hematoma and a subdural hematoma may be difficult and sometimes impossible. The purpose of this paper is to review and analize the radiographic findings of 23 epidural and 45 subdural hematomas, which were surgically proven at S.N.U. Hospital during the period from July 1972 through July 1975, with emphasis on differential diagonstic aspects. Roentgen analysis is based on incidence of skull farcture, shape of avasular zone and various characteristic angiograhic signs. The results are as follows: 1. Simple skull roentgenograms reveal fractures in 19 cases out of 23 epidural hematomas and in 18 cases out or 45 subdural hematomas. None of 8 chronic subdural hematomas shows skull farcture. 2. On cerebral angiography, epidural hematomas reveal typical lentiform avascular zone in 10 cases, semilunar shape in 2 cases and crescent shape in 3 cases, while subdural hematomas reveal crescent avascular zone in 18 cases, emilunar avascular zone in 4 cases and lentiform in 3 cases. 3 lentiform avascular zones of subdural hematoma are all found in cases of chronic stage and over 40 years of age. 3. In epidural hematomas, extravasation of contrast media (7 cases), displacement of dural sinus from inner tables(5 cases), medial displacement of middle meningeal artery (3 cases), amputation of middle meningeal artery (1 case) and pseudoaneurysm of middle meningeal artery (1 case) were observed, while only one case of extravasation of contrast media was observed in subdural hematomas.