Between January 1973 and October 1991 at the Mayo Clinic, 5 of 345 patients with Wegener's granulomatosis initially had features suggestive of giant cell arteritis and subsequently were found to have biopsy-proven vasculitis of the temporal artery. All five patients were older than 60 years of age and had jaw claudication, sudden loss of vision, severe headache with or without diplopia, or polymyalgia rheumatica at the time of initial examination. The erythrocyte sedimentation rate was high at the time of onset of symptoms in four patients (and unavailable in one patient). A temporal artery biopsy specimen revealed giant cell arteritis in one patient and non-giant cell arteritis in four patients. All five patients subsequently had pulmonary and renal lesions characteristic of Wegener's granulomatosis, with typical histopathologic features on biopsy or positive cytoplasmic staining antineutrophil cytoplasmic antibodies. Thus, overlapping features of giant cell arteritis and Wegener's granulomatosis do occur in some patients.