Three patients with acute subdural hematoma (SDH) caused by a ruptured intracranial aneurysm were admitted in a comatose state with signs of cerebral herniation. In one patient, while the SDH was evacuated by an emergency craniotomy, cerebral angiography was performed. Aneurysmal neck clipping was performed during the same operation. The man made a good recovery. In the other patients, while the SDH was irrigated by emergency trepanation, cerebral angiography was performed. These hepatomas were inoperable and the 2 patients died the day after admission. Several recent reports have suggested that SDH evacuation with craniotomy and aneurysmal neck clipping should be conducted simultaneously. However, the start of a one-stage operation for SDH and ruptured aneurysm is usually delayed several hours due to the need for preoperative examinations including angiography. A portable digital imaging system (PDIS) showing real time subtraction images is useful for finding critical vascular anomalies. The authors emphasize that a one-stage operation can be started within 50 minutes after admission by using a PDIS.