227 patients underwent 259 carotid endarterectomies because of transitory ischemic attacks (TIA). All had a 50% or more carotid lumen reduction as revealed by angiography, and symptoms from the arteriosclerotic lesion. Surgical mortality/morbidity at 30 days was 2.6%. 5.3 years after the operation (1 month-13 years) the probability of stroke was 4.9%, which corresponds to a postendarerectomy stroke rate of 1% per year. The procedure may be of value if the rate of surgical complication is very low, but the net effect still depends upon the occurrence of other vascular complications during the follow-up period. The incidence of vascular diseases in this series of seriously affected arteriosclerotics was higher than in a matched normal population, and mortality was much higher. At present a somewhat restrictive indication for surgery seems justified.