Four cases of delayed post-traumatic epidural hematoma which had not been present on initial CT scan were found on repeated CT scan. The delayed epidural hematoma was developed after evacuation of a hematoma in all cases. And a skull fracture was present at the site of the delayed hematoma in two cases. The neurologic deterioration heralded the onset of delayed epidural hematoma after decompressive therapy by either surgical or medical means. Repeated CT scan is indicated if anticapated improvement from does not occur after decompression by either surgical or medical means, recovery from shock, or whenever there is evidence of even minimal bleeding under a skull fracture on the initial CT scan.