HCV infection has been associated with a broad spectrum of extrahepatic manifestations. In some of these, such as mixed cryoglobulinaemia (MC), the association is firmly established, whereas in others, such as polyarteritis nodosa (PAN), it is anecdotal; in fact, in this disorder the importance of the association is controversial, since it seems to be related to the frequent coinfection of HBV and HCV. The pathogenesis of MC and PAN is far from clear, but recent developments have added a plethora of information on the mechanisms underlying these disorders. Although both could be induced by a viral infection, the pathophysiological processes underlying the two diseases are different. We describe the occurrence in the same patient of HBV-related PAN and HCV-related MC.