Forty-five patients with symptomatic (20 with transient ischemic attack, 25 with minor stroke) greater than or equal to 75% stenosis of the cervical internal carotid artery had no endarterectomy and received only medical therapy because the surgical risks (severe cardiac disease, chronic obstructive pulmonary disease, hypertension or diabetes with systemic complications, aortic aneurysm) were believed to be unacceptable. During follow-up (mean 48 months), occlusion of the internal carotid artery developed without symptoms in two patients and with symptoms in three patients. The cumulative stroke and/or death rate was 24% at 2 years and 50% at 6 years. The ipsilateral infarct rate was 10% after the first year, but decreased markedly thereafter (2.4% per year), and one third of these infarcts were probably lacunes due to hypertensive small vessel disease. Overall, stroke related to previously symptomatic internal carotid artery stenosis was not the major problem during follow-up but was largely overcome by other strokes and cardiac death.