The efficacy and safety of recombinant interferon-alpha 2b (rIFN-alpha 2b) was evaluated in a double-blind controlled trial comprising 23 haemodialysis patients with antibodies to hepatitis C virus (anti-HCV), detectable serum HCV RNA by polymerase chain reaction and chronic alanine aminotransferase elevation. The patients were randomly assigned to receive rIFN-alpha 2b at a dose of 1.5 MU (increasing to 3 MU if no response was observed) (Group I: n = 14) or identical placebo (Group II: n = 9), for 6 months. A biochemical response (normal alanine aminotransferase) was observed in 10 patients (71.4%) from Group I and in one patient (11.1%) from Group II (P < 0.01) at the end of therapy, and in four patients from Group I (28.6%) and in none from Group II (NS) 12 months after therapy. Virological response (HCV RNA negative) was observed in four patients (28.6%) from Group I and in none from Group II (NS) at the end of therapy, and in two patients (14.2%) from Group I and in none from Group II (NS) 12 months after therapy. Interferon doses were 1.5 MU in 12 patients and 3 MU in two patients. Therapy interruption owing to severe side-effects was necessary in three patients (21.4%) from Group I and in two patients (22.2%) from Group II. Although long-term statistical differences were not observed, these results suggest that rIFN-alpha 2b at a low dose is a reasonable and well tolerated therapeutic approach for haemodialysis patients with chronic hepatitis C.