Chronic hepatitis C is endemic among chronic haemodialysis patients. There have been a number of reports on hepatocellular carcinoma developing in such patients in Japan. The present study reports on the treatment of 15 patients who showed elevated ALT levels due to biopsy proven chronic hepatitis C with interferon alpha-2a (IFN). The dose schedule was 6 mega units (MU) daily for the first two weeks followed by 3 doses per week for 5.5 months. Side effects were so severe that IFN treatment was discontinued early in one patient, the dosage reduced in 11 and only tolerated in the original schedule by three patients. Excluding one patient who only recently completed the therapy, 13 were able to be evaluated for therapy efficacy by assessment of serum ALT and viral RNA. The overall results showed that IFN was effective in eight of 13 patients, a rate somewhat higher than the reported figures in this country. It is concluded that IFN therapy is indicated in haemodialysis patients with progressive chronic hepatitis C, but the dose administered should be lower and the dose schedule more flexible, perhaps 3 MU three times a week, in order to minimize untoward side effects.