Hepatitis C virus has been proven to be the major cause of NANB hepatitis, cirrhosis and hepatocellular carcinoma worldwide. Based on the genome similarities between HCV and flavivirus or pestivirus, this agent has been included within the family Flaviviridae as a separate genus. Among the analogies between HCV and the other members of the same family there is the possibility of infecting blood cells. In particular, significant evidence obtained through studies performed in vivo and in vitro support the concept that HCV is not only a hepatotropic but also a lymphotropic virus. This suggests that, in addition to playing a role in inducing hepatic diseases (both of a non-tumoral and a neoplastic nature), HCV infection may also play a role in extrahepatic pathologies. The striking association observed between HCV infection and some autoimmune-lymphoproliferative disorders of either benign or neoplastic nature is consistent with this hypothesis. However, in analogy with what has been observed in the case of liver disease, the mechanisms involved in the pathogenesis of HCV-related extra-hepatic manifestations have to be more deeply analysed and clarified.