The present study includes 38 patients treated surgically for ruptured aneurysm manifesting subarachnoid hemorrhage without intracerebral hematoma, evaluating clinical grade at admission, secondary development and management of early cerebral swelling, subsequent complications such as cerebral infarction caused by vasospasm, and clinical outcome. Six of 32 patients treated by early surgery within 24 hours developed critical cerebral swelling in the early period after SAH. Five of these 6 patients received barbiturate therapy. Two patients died of advancing cerebral swelling. Three of 5 patients who received barbiturate therapy showed good recovery without any neurologic deficit, 1 suffered intellectual impairment, and the other 1 died. Serial computed tomography (CT), CT angiography, and dynamic CT evaluated elapsing of cerebral swelling, progression of cerebral vasospasm, and change of cerebral blood perfusion (flow) in 2 patients who suffered early cerebral swelling. In these 2 patients, progression or persistence of vasospasm was recorded for a longer period, whereas the cerebral swelling resolved within a short period. Cerebral infarction caused by vasospasm was seen in 8 of these 38 surgical cases, and hydrocephalus was seen in 15 of 38 cases. All 4 survivors after early cerebral swelling developed hydrocephalus and underwent shunting. Development of cerebral swelling in patients with ruptured aneurysm greatly affects outcome. Although barbiturate therapy is useful for the treatment of patients who suffer serious cerebral swelling, improvements in management may be required.