A patient with a history of migraine without aura developed a complete left III nerve palsy a day after the onset of bilateral throbbing headache associated with vegetative symptoms. Magnetic resonance imaging showed a hemorrhagic pituitary adenoma as the probable cause of the symptoms, presumably by a compressive mechanism. This case suggests a further possible cause of ophthalmoplegia associated with migraine and confirms the clinical utility of magnetic resonance imaging in the differential diagnosis of ophthalmoplegic migraine and other conditions in which the symptomatology is secondary to intracranial lesions.