The relationship between the results of early operation for ruptured intracranial aneurysms (72 cases) and the preoperative computed tomographic (CT) findings was studied. There was a correlation among the surgical results, the development of symptomatic vasospasm, and high density on the preoperative CT scan, particularly the presence of a localized, thick layer in the subarachnoid space. However, no relationship was found between the occurrence of ventricular enlargement and the preoperative CT findings. Cisternal or ventricular drainage might contribute to an uncomplicated postoperative course for patients with severe subarachnoid clot shown on the preoperative CT scan.