Clinical and laboratory evidence of liver involvement are frequently found in essential mixed cryoglobulinaemia (EMC). We looked for evidence of hepatitis C virus (HCV) infection in 37 patients with EMC. Anti-HCV antibodies (Ab) were found in 16/37 (43%) patients with EMC using the ELISA 2 test and the RIBA 2 test. The 16 anti-HCV-Ab positive patients (group 1) were compared to the 21 anti-HCV-Ab negative patients (group 2). Group 1 patients had more frequent cutaneous involvement (P = 0.02), clinical, biological and histologic hepatic involvement (P < 0.01), higher serum cryoglobulin and lower CH50 levels (P < 0.001). Serum hepatitis B virus markers were infrequent in both groups and no patient from either group had detectable serum HBV DNA. These preliminary results suggest that HCV may be another cause of mixed cryoglobulinaemia.