In polyarteritis nodosa (PAN) due to hepatitis B virus (HBV) infection, the insidious nature of the infection makes very difficult to establish the chronology which often remains unknown. PN occurs in the majority of patients during the year following infection. Simultaneous occurrence or occurrence immediately after infection with the HBV is exceptional. We report here three cases of this form of simultaneous HBV infection and PN and describe the particular clinical, virological and evolutive features of the disease.