The authors studied the charts and angiograms of 178 patients with cerebral vascular lesions. The angiographic features of these malformations could be grouped into the following categories: arterial variations, arterial aneurysms, arterial infundibulum, arterial stenosis, venous variation, venous stenosis, venous ectasia, arteriovenous fistula, transcerebral vascularization and external carotid supply. The age and sex of the patients as well as the topography and angiographic features were correlated with the incidence of hemorrhage. We found that deep and posterior fossa malformations, as well as temporal, insular and callosal localizations, were more likely to have bled. We also found that older males (40-50 years) with associated aneurysms and younger females (20-30 years) with venous stenosis were more likely to have bled.