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 findingsof 23 epidural and 45 subdural hematomas, which were surgically proven at S.N.U. Hospital during the period fromJuly 1972 through July 1975, with emphasis on differential diagnostic aspects. Roentgen analysis is based onincidence of skull fracture, shape of avascular zone and various characteristic angiographic signs. The resultsare as follows : 1. Simple skull roentgenograms reveal fractures in 19 cases out of 23 epidural hematomas and in18 cases out of 45 subdural hematomas. None of 8 chronic subdural hematomas shows skull fracture. 2. On cerebralangiography, 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, semilunaravascular zone in 4 cases and lentiform in 3 cases. 3 lentiform avascular zones of subdural hematoma are all foundin 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 table (5 cases), medial displaceent 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.