Twenty-five per cent of haemodialysed patients carry anti-HCV antibodies; these antibodies are associated with detectable viraemia in 85% and chronic hepatitis in 90% of subjects, despite normal transaminases in more than half of them. This underlines the importance of antiviral therapy. We evaluated the tolerance and effectiveness of a classic interferon (IFN) treatment (3 MU three times a week for 6 months, subcutaneously) in 19 haemodialysis patients presenting with anti-HCV antibodies and chronic (n = 16) or acute (n = 3) hepatitis. Thirteen of those 19 patients had elevated transaminases. Viraemia C was detected by genome amplification (PCR) and by the bDNA test before and after interferon therapy as well as 6 months at least after the end of INF treatment. Response (defined as liver enzyme normalization) was noted in 11 (84.6%) of the 13 patients with elevated transaminases; at the end of follow-up, six exhibited long-term response and five had relapsed, HCV-RNA was detected in 15 of the 19 patients before IFN therapy and remained positive in 7/15 initially viraemic patients at the end of treatment. Hepatitis C RNA was detected at the last follow-up visit (mean follow-up duration 18 +/- 9 months) in 12 of the 15 initially viraemic patients. Liver histology was improved in most patients, regardless of their biological response. One patient could not complete the 6-month course because of clinical and haematological adverse events. In the six patients with strictly normal transaminases, HCV RNA was detectable in 4/6 patients before treatment, in 2/4 viraemic patients at the end of treatment, and in 4/4 at the last follow-up visit. All pathological signs disappeared in four of the five patients who had no detectable HCV-RNA before IFN therapy. To conclude: (i) interferon-alpha exhibits satisfactory effectiveness and tolerance in haemodialysed patient; (ii) HCV replication recurs in most of these patients despite histological improvement; (iii) interferon-alpha can be effective even in patients with chronic hepatitis and no detectable HCV-RNA.