Summary. Hepatitis C virus (HCV) infection is common in transfusion-dependent thalassaemia. The clinical usefulness of 12-month treatment, using interferon alpha 3 MIU/m2 thrice weekly and oral ribavirin 16 mg/kg/d, was evaluated in 18 previously untreated thalassaemia patients. The median age at start of treatment was 16 years (range 7–29). Fourteen were infected with genotype 1b and 4 with genotype 6a. The sustained biochemical and virological response rates 6 months after stopping treatment were both 72·2%. Blood consumption was temporarily increased by 30% due to ribavirin-associated haemolysis. This study demonstrated a high, sustained response rate to combination treatment despite infection with genotype 1b.