PURPOSE: To describe a patient whose initial sign of giant cell arteritis was a branch retinal artery occlusion. METHODS: We examined a 77-year-old woman who developed arteritic anterior ischemic optic neuropathy three weeks after an isolated non-embolic branch retinal artery occlusion occurred in the same eye. RESULTS: The diagnosis of giant cell arteritis was confirmed by temporal artery biopsy after the patient was treated with intravenous corticosteroids. CONCLUSIONS: Although a rare cause of branch retinal vascular occlusion, giant cell arteritis should be considered in the differential diagnosis of a non-embolic branch retinal artery occlusion in elderly patients.