OBJECTIVE An open, uncontrolled trial of ribavirin, an oral guanosine nucleoside analog for treatment of hepatitis C, in patients with hepatitis C virus (HCV) associated cryoglobulinemia intolerant to interferon. METHODS Five patients with cryoglobulinemia related to HCV infection unresponsive to interferon therapy received oral ribavirin (100 to 1200 mg daily) for 10 to 36 months. RESULTS Patients treated with ribavirin had prompt decrease in serum aminotransferase levels and marked improvement of manifestations of cryoglobulinemia within a few weeks. Ribavirin did not eradicate HCV RNA from the sera, but a decrease in viral load was observed in 3 patients, from 232 to 86 x 10(5) copies HCV/ml. Relapse occurred within 3 months once therapy was discontinued. The drug was well tolerated, but mild dose related hemolysis was common. CONCLUSIONS Ribavirin monotherapy may be effective in patients with symptomatic cryoglobulinemia related to HCV infection, but this effect is not sustained when ribavirin therapy is discontinued.