Three-dimensional computed tomographic angiography (CTA) is a noninvasive technique for detecting lesions after acute subarachnoid hemorrhage. We encountered extravasation on CTA, a finding that has not been reported previously. Three patients with saccular aneurysms showed extravasation on CTA performed within 3 h of the onset of hemorrhage, and all three patients died within 2 weeks. At autopsy, the site of rupture of the aneurysm was confirmed in all three cases. There were two patterns of extravasation shown by CTA, which seemed to depend on the direction of rupture. Extravasation on CTA might represent the natural progression of ruptured aneurysm and may indicate a poor prognosis.