We report a 73-year-old patient with giant cell arteritis who presented with right arm paresis and dysarthria. Vasculitis of the vertebral arteries induced multiple ischemic cerebral lesions in the vertebrobasilar territory, ultimately leading to death despite intensive immunosuppressive therapy. This case illustrates that prompt relief from symptoms of giant cell arteritis upon steroid treatment does not correspond to a remission of the vasculitic process itself. Clinicians should therefore be aware of the possible occult involvement of the vertebral or other major arteries.