Although essential mixed cryoglobulinaemia (EMC) is recognized to be frequently associated with chronic liver disease, aetiology and pathogenesis of liver damage remain unsolved questions. The purpose of this study was to assess the possible causative role of hepatitis C virus (HCV) in the liver impairment occurring in patients with EMC. Twenty-six consecutive EMC patients were evaluated. All patients underwent percutaneous liver biopsy. Anti-HCV antibodies were assayed by ELISA and supported by a recombinant immunoblotting assay (4-RIBA). The prevalence of anti-HCV antibodies in patients with and without chronic active liver disease (CALD) was compared. Anti-HCV antibodies were detected in 13 patients (50%) by ELISA and confirmed in 11 of them (42.3%) by 4-RIBA, the remaining two patients being indeterminate in the supportive assay. CALD correlated significantly with anti-HCV antibodies: indeed, 7/11 (63.6%) anti-HCV+ patients showed histological and clinical pictures of CALD, compared with 1/15 (6.6%) anti-HCV- patients (P less than 0.01). With the exception of the patient who was found to be HBsAg+, no liver tissue expressed hepatitis B virus-related antigens in the hepatocytes. Additional histological findings included discrete lymphoid aggregates in portal tracts, siderosis, fatty changes, hyperplasia of Kupffer cells. It can be concluded that chronic liver damage in EMC is frequently associated with anti-HCV antibodies. Although the cause of EMC remains unknown, this study has obvious implications for clarifying the etiology of associated CALD and further supports the therapeutic use of interferons in this disease.