Of 248 patients with giant cell arteritis, 34 had evidence that the disease affected the aorta or its major branches. Symptoms suggestive of large artery involvement were intermittent claudication of an extremity, paresthesias, and Raynaud's phenomenon. Physical findings included absent or decreased large artery pulses and bruits over large arteries. Four patients presented with decreased upper extremity pulses as the initial manifestation of their arteritis. Nine other patients under treatment for temporal arteritis or polymyalgia rheumatica first developed evidence of large artery involvement as corticosteroid therapy was tapered or discontinued. Angiography, performed in 10 patients, was helpful in indicating arteritis rather than atherosclerosis as the cause of large artery disease. Three patients died with aortic rupture, and, at autopsy, widespread giant cell arteritis was found. However, when corticosteroids were given in adequate doses, the response was favorable in most patients; intermittent claudication decreased and the pulses improved.