Hepatitis B virus-associated polyarteritis nodosa (HBV-PAN) is a typical form of classic PAN whose pathogenesis has been attributed to immune-complex deposition with antigen excess. We conducted the current study to 1) analyze the frequency of HBV infection in patients with PAN, in light of the classification systems described since 1990; 2) describe the clinical characteristics of HBV-PAN; 3) compare the evolution according to conventional or antiviral treatment; and 4) evaluate long-term outcome. One hundred fifteen patients were included in therapeutic trials organized by the French Vasculitis Study Group and/or referred to our department for HBV-PAN between 1972 and 2002. To determine the frequency of HBV-PAN during the 30-year period, we analyzed a control group of patients with PAN without HBV infection, followed during the same period and diagnosed on the same bases. Depending on the year of diagnosis, different treatments were prescribed. Before the antiviral strategy was established, some patients were given corticosteroids (CS) with or without cyclophosphamide (CY). Since 1983, treatment for patients with HBV markers has combined 2 weeks of CS followed by an antiviral agent (successively, vidarabine, interferon-alpha, and lamivudine) combined with plasma exchanges (PE).Ninety-three (80.9%) patients entered remission during this period and 9 (9.7%) of them relapsed; 41 (35.7%) patients died. For the 80 patients given the antiviral strategy as intention-to-treat, 4 (5%) relapsed and 24 (30%) died vs 5 (14.3%) relapses (not significant [NS]) and 17 (48.6%) deaths (NS) among the 35 patients treated with CS alone or with CY or PE. HBe-anti-HBe seroconversion rates for the 2 groups, respectively, were: 49.3% vs 14.7% (p < 0.001). Patients who seroconverted obtained complete remission and did not relapse.Thus, HBV-PAN, a typical form of classic PAN, can be characterized as follows: when renal involvement is present, so is renal vasculitis; glomerulonephritis due to vasculitis is never found; antineutrophil cytoplasmic antibodies (ANCA) are not detected; relapses are rare, and never occur once viral replication has stopped and seroconversion has been obtained. Combining an antiviral drug with PE facilitates seroconversion and prevents the development of long-term hepatic complications of HBV infection. The major cause of death is gastrointestinal tract involvement. Importantly, the frequency of HBV-PAN has decreased in relation to improved blood safety and vaccination campaigns.