The purpose of this study was to review the positive angiographic findings in patients with polyarteritis nodosa (PAN). The authors reviewed the angiograms of 56 consecutive patients (25 women and 31 men; age range, 18-81 years; mean age, 55 years) with PAN and arterial abnormalities consistent with necrotizing vasculitis. Aneurysms were present in 27 patients and segments of ectasia were present in seven patients, for a total of 34 (61%) of 56 patients with aneurysmal lesions. The remaining 22 (39%) patients had arterial lesions that were occlusive: luminal irregularity, stenosis, or occlusion. All but one of the patients with an aneurysm also had occlusive lesions. Therefore, 55 (98%) of the 56 patients were found to have occlusive lesions. Skeletal muscle arteries were affected in 18 patients, nine in the extremities. The most frequent finding in patients with PAN was occlusive arterial lesions. Although the presence of aneurysms increases specificity for the diagnosis of PAN, many patients have only occlusive lesions. Involvement of skeletal muscle arteries was common.