This trial was undertaken to establish the long term biochemical and serological outcome of patients with acute post-transfusion hepatitis C virus infection after treatment with interferon alfa-2b. After 12 months, 12 patients (eight treated, four controls) had self limited disease and 16 patients (seven treated, nine controls) had chronic disease. After a total mean 31 months of follow up in 23 patients, nine (six treated, three controls) had self limited disease while 14 (five treated, nine controls) developed chronic liver disease; all patients with spontaneous or self limited hepatitis C (HCV) infection maintained normal serum alanine amino-transferase activity and absence of HCV-RNA, and tended to lose anti-HCV antibodies.