We describe four patients with cerebral infarction and active neurosyphilis who had variable angiographic findings. Patients 1 and 2 had evidence of arteritis and an atheromatous ulcerated stenosis of the extracranial carotid artery, respectively. The third and fourth patients had symptoms of lacunar infarction, but cerebral angiography was normal in patient 3, whereas patient 4 had evidence of concomitant atheromatous and arteritic lesions. Neither age nor presence of cerebrovascular risk factors was of aid in predicting angiographic features. The concomitance of cerebral infarction and active neurosyphilis does not imply a cause-and-effect relation, since atherosclerotic lesions may coexist with arteritis or may even represent the only angiographic feature. Our findings underscore the importance of angiography to confirm the diagnosis in cases of suspected syphilitic arteritis.