Arteriovenous malformations (AVMs) of the brain usually present with acute hemorrhage or epilepsy. Of 54 patients with AVMs limited to the posterior cerebral hemispheres some 60% had intermittent or acute visual symptoms. Most had homonymous hemianopia. Because of the possible neurologic consequences of an AVM it is important to distinguish the headaches and visual symptoms of this lesion from those of classic migraine, a more common condition. In this paper this differentiation and the pathogenesis of the symptoms are reviewed.