A 67-year-old man presented with recurrent clinically diverse posterior circulation transient ischemic attacks which continued despite full anticoagulation. Giant cell arteritis was suspected because of a markedly elevated erythrocyte sedimentation rate and confirmed by temporal artery biopsy. Treatment with corticosteroids resulted in a prompt and enduring resolution of clinical symptoms. Giant cell arteritis may represent a treatable cause of posterior circulation transient ischemic attacks, uniquely responsive to corticosteroids.