BACKGROUND Because of the transient and rare nature, objective visual and neuroimaging evaluation during an acute, spontaneous attack of a migrainous aura causing a complete homonymous hemianopia has not been reported. METHODS A healthy 27-year-old white woman with a history of typical aura with migraine presented during an episode of no light perception in the right hemifield of both eyes. Ophthalmic testing and neuroimaging were unremarkable. The visual field defect started to resolve 1 hour after initial symptoms, and significant improvement was seen after 4 hours. One year later, the patient had no visual field defects and had not experienced another episode of homonymous hemianopia. CONCLUSIONS More than one third of migrainous patients experience visual symptoms. Typical aura with migraine is diagnosed usually by history. Laboratory testing and neuroimaging are necessary if an alternative cause is suspected, i.e., the aura begins after age 40 years, negative features are predominant, or the aura is very short or prolonged. Correct diagnosis is critical, because conditions that mimic migrainous aura have potentially devastating consequences. Migraine with aura patients may have persistent visual field defects and are at an increased risk for stroke compared with nonmigraine patients. This case improves our knowledge of the nature of a transient homonymous hemianopia associated with migraine.