Nineteen haemodialysis (HD) patients with chronic hepatitis C were treated with interferon-alpha 2b (IFN-alpha) at a dose of 3 or 1 MU thrice weekly for 6 months and were followed-up for another 14 months without treatment. Six patients discontinued treatment because they either presented severe side-effects to IFN-alpha or had complications of their primary disease. Levels of AST and ALT were within normal limits on the 2nd month of treatment and remained so throughout the treatment and the follow-up period in all patients except one who showed an elevation of transaminase levels 2 months after the end of treatment. Serum HCVRNA became negative in 10/13 patients at the end of treatment and was negative in all patients on the 6th month and in 12/13 patients on the 14th month during the follow-up period. Levels of 2'5' oligosynthetase were increased significantly on the 2nd and 4th month of treatment and returned to pretreatment values the 2nd month after treatment. These findings demonstrate that haemodialysis patients with chronic hepatitis C respond well to interferon treatment and that a long-term response is achieved in a high proportion of patients.