This study assesses the efficacy and adverse effects of interferon-alpha (IFN-alpha) administered at a dosage of 3 million units three times weekly for 1 year in 17 hemodialysis patients with hepatitic C virus (HCV)-associated chronic hepatitis (biopsy proven), The patients were prospectively followed up for a period of 18 months, Liver biopsy was repeated after 6 months of treatment in 13 patients. Patients were classified according to the histological activity index. Biochemical and virological responses were evaluated at the end (end-of-treatment response) and 6 months after completion of therapy (sustained response), HCV RNA became negative in 76% of the patients after 12 weeks of treatment, in 88% after 12 months of treatment, and in 71% of the patients 6 months after completion of therapy, HCV genotype 4 was found in 60% of our population. Alanine aminotransferase (ALT) levels were initially increased in only 6 patients and normalized in 4 of these patients after 12 weeks of therapy, with end-of-treatment and sustained biochemical responses of 83% and 67%, respectively. Of 13 patients who underwent liver biopsies after 6 months of therapy, 11 patients (85%) showed histological improvement, One patient could not tolerate therapy because of marked lethargy and myalgia; the other patients had minor side effects that did not require discontinuation of treatment. Two patients received a cadaveric renal transplant after 1 year of IFN treatment, and they continued to maintain biochemical and virological responses after a follow-up of 17 and 28 months, respectively, (C) 1999 by the National Kidney Foundation, Inc.