Between 1985 and 1995, 47 patients with evidence of polyarteritis nodosa were seen at the department of Internal Medicine. Thirty-nine patients fulfilled histological and/or arteriographic diagnostic criteria, and in eight patients, the diagnosis was based on clinical criteria. At the onset of the disease, 25 patients were below the age of 65 (group A) and 22 were above the age of 65 (group B). Except for increased frequency of weight loss in group B and increased frequency of cutaneous signs (purpura and nodes) in group A, no significant differences were found in clinical and biological features. The mean duration of follow-up was 46.9 +/- 36.5 months. The number of deaths was significantly higher among the elderly (ten deaths in group B versus two in group A).