Standard treatment for chronic hepatitis C is with interferon (IFN)-alpha and ribavirin for 6-12 months. In dialysis patients only interferon therapy is currently used due to the lack of knowledge concerning ribavirin dosage and side-effects. The aim of this study was to investigate if ribavirin can be added to interferon when treating dialysis patients with hepatitis C. Five patients on haemodialysis and one patient on peritoneal dialysis with chronic hepatitis C, five with genotype 1 and one with genotype 4, were given interferon-alpha2b 3 MU thrice weekly for 4 weeks, whereafter ribavirin 200-400 mg was added, for an intended total treatment period of 28 weeks. Ribavirin plasma concentrations were monitored, using HPLC. Four patients completed the treatment. One patient suffered marked side-effects from interferon and therapy was terminated. One patient developed heart failure and died after 14 weeks of treatment but the death was not considered treatment related. Based on plasma concentrations, ribavirin doses were frequently adjusted initially. The target concentration (10-15 micromol/L) was reached with average daily doses of 170-300 mg ribavirin. Ribavirin induced anaemia was managed with high doses of erytropoietin (20 000-30 000 IU/week). Five of six patients became hepatitis C virus (HCV)-RNA negative during treatment, but four relapsed post-treatment; one is HCV-RNA negative. Hence ribavirin, in combination with IFN-alpha, can be used to treat dialysis patients with HCV. However, this requires reduced ribavirin doses and close monitoring of ribavirin plasma concentrations and haemoglobin. Ribavirin-induced anaemia can be managed with high doses of erythropoeitin.