In order to evaluate the effectiveness of combined carotid and coronary surgery in reducing the incidence of neurological disturbances after coronary artery bypass grafting (CABG), 144 consecutive candidates for CABG (group I) were screened for carotid disease noninvasively with Doppler ultrasonography (duplex). Twenty-six (18%) were considered at risk for stroke because of a severe (above 50% diameter reduction) stenosis; 20 (4 symptomatic and 16 asymptomatic) underwent combined surgery. Forty-seven other patients (group II) underwent CABG surgery without previous Doppler investigation. Only three patients (1.5% of the survivors) developed transient neurological disturbances after surgery; two who had normal internal carotid arteries belonged to group I, and one to group II. None of the six patients at risk for stroke who underwent only CABG developed neurological symptoms. The incidence of intra- and postoperative cardiac complications of the group who had CABG only compared to that of the group with combined surgery. We conclude that, although safe, combined surgery is not to be performed systematically on candidates for CABG with a significant internal carotid artery stenosis.