Cerebral vasospasm is one of the most serious complication after subarachnoid hemorrhage due to aneurysmal rupture. To date, the treatment of vasospasm remains unsatisfactory in a large numbers of cases in spite of recent therapeutic advances. Prompt diagnosis of this complication, before the establishment of lasting ischemic damage, should obviously improve the results of treatment. The possibility of predicting which patients will develop vasospasm, constitutes a further advance in the management of this complication. In this study, the value of the computed tomographic scan for the prediction of vasospasm was investigated in a consecutive series of 67 patients submitted to computed tomography within 7 days of the most recent subarachnoid hemorrhage.