A 72-year-old woman with previously symptomatic internal carotid artery occlusion subsequently presented with an acute hemispheric deficit. The patient was initially diagnosed as having an ischemic infarction but eventually was shown to have a subacute subdural hematoma with delay in surgical evacuation and a major permanent deficit. We speculate that internal carotid artery occlusion may predispose the patient to greater morbidity from subdural hematoma. Patchy hemispheric infarction may reflect greater vulnerability to extrinsic hemispheric compression in the setting of carotid occlusion. This case illustrates the necessity for vigorous pursuit of the diagnosis of subdural hematoma in patients presumed to have transient ischemic attacks or acute cerebral infarction.