Fibromuscular disease of the carotid artery was identified in 30 patients, which represented 3.2 percent of all patients who had cerebral angiography at Brooke Army Medical Center in the 6 year period from 1978 to 1984. Focal neurologic events were the presenting symptoms in 63 percent of the patients. The majority of the patients were treated with antiplatelet therapy, and eight patients had a total of 10 carotid artery dilatations. The only patients with recurrent symptoms were those who received either no treatment or antiplatelet therapy. There were no recurrent symptoms in the operated patients. This study suggests that surgical treatment for the symptomatic patient may prevent recurrent symptoms with an acceptably low morbidity and mortality. There was, however, no indication that prophylactic dilation of the fibromuscular disease in the asymptomatic patient was beneficial. Fibromuscular dysplasia of the carotid arteries is often associated with intracranial aneurysms, and surgical therapy rather than antiplatelet therapy may be advisable in patients who have intracranial aneurysms. Patients with concomitant atherosclerosis of the carotid artery bifurcation should be treated like any patient with atherosclerotic disease and an endarterectomy should be performed with carotid dilatation when indicated. Fibromuscular disease of the carotid artery is an infrequent angiographic finding that is associated with focal and global neurologic symptoms. Most patients can be effectively treated with antiplatelet drugs with no recurrent symptoms, however, for persistent or progressive symptoms, some patients will require surgical dilatation of the carotid artery. Fibromuscular disease of the carotid artery may lead to catastrophic symptoms of stroke or intracranial hemorrhage if left undiagnosed or untreated.