Fusiform aneurysms of the basilar artery are extremely unusual. Most show signs of a posterior fossa mass. One case is reported which presented with recurrent transient ischemic attacks suggesting carotid vascular disease. Failure of an appropriate endarterectomy to relieve the symptoms, and later brain stem infarction, led to the correct diagnosis. Whenever recurrent or new symptoms appear following carotid vascular surgery, other diagnoses must be considered.