Management of the asymptomatic carotid bruit remains a controversial subject. The purpose of this study is to determine whether or not such bruits are important risk factors in the evolution of stroke. Since April 1977, 87 patients with 131 asymptomatic carotid bruits were evaluated with the Gee oculoplethysmography (OPG). Eleven bruits (8.4%) were hemodynamically significant (ophthalmic artery/brachial artery systolic pressure index below 0.69 or a difference of 5 mm Hg or more between the eyes). The patients were reevaluated at 6-month intervals. The mean follow-up was 34 months (range, 1-60 months). During this period, 14 bruits (11.6%) that initially were nonhemodynamically significant (NHS) later became hemodynamically significant (HS). Patients with asymptomatic carotid bruits had a stroke incidence of 10.3 per cent. Patients with HS bruits had a stroke incidence of 24 per cent and a transient ischemic attack (TIA) incidence of 16 per cent, which were significantly higher (P greater than 0.01) compared to the patients with NHS bruits (4.8% incidence of stroke and 3.2% incidence of TIA). Nine patients (10.3%) developed strokes without antecedent TIA and six patients (6.9%) developed TIA. The strokes occurred in the cerebral hemisphere supplied by the carotid artery with HS bruit in three of six patients. The strokes in three patients with NHS bruits were on the same side of the bruits. The TIAs developed in four patients with HS bruits and in two patients with NHS bruits. The authors conclude that the patient with an asymptomatic HS carotid bruit has a high risk of developing a stroke and that surgical treatment is warranted.