Two patients with histories of migraine had ischemic optic neuropathy develop during an episode of migraine. Clinical and radiologic studies excluded other causes of visual loss. Fluorescein angiography confirmed as ischemic process involving the optic dis. In both cases, visual loss was permanent. No further visual disturbance has occurred in either patient during a two-year period of follow-up while taking oral doses of propranolol hydrochloride.