Carotid atherosclerosis is commonly detected in the asymptomatic elderly and in patients with known vascular disease in other distributions. Although there has been considerable interest in carotid bruits, they are not a reliable indicator of asymptomatic stenosis. In patients with asymptomatic stenosis detected by carotid ultrasound or angiography, the annual risk of ipsilateral infarction is approximately 1% to 2%. If ischemic events occur, they are usually transient ischemic attacks. Stroke risk is higher when there is progressive stenosis, stenosis exceeding 75% to 80%, and, possibly, complicated plaque-morphologic characteristics. The treatment of asymptomatic carotid stenosis remains controversial. Antiplatelet agents are of unproven value in asymptomatic patients. The role of surgical management is disputed because of uncertainties regarding the natural history of asymptomatic stenosis and the efficacy and complication rates of endarterectomy. Pending results of several ongoing randomized clinical trials, it may be advisable to withhold endarterectomy from those asymptomatic patients with stenosis of less than 75% to 80%. Prophylactic carotid endarterectomy is not necessary in the patient with asymptomatic stenosis who will undergo another operative procedure such as coronary artery bypass.