Many haemophilia patients were infected with hepatitis C virus (HCV) in childhood after transfusion with inadequately or non-virus inactivated clotting factor products. Limited information is available on the clinical course of HCV infection in children. To assess the clinical consequences of hepatitis C in these young patients we performed a pilot study of 31 patients with haemophilia, infected with HCV before the age of 13. Current median age was 20 years. Nineteen (61%) patients had chronic hepatitis C, whereas the remaining 12 patients spontaneously cleared HCV. The median duration of infection was 17 years. Among patients chronically infected with HCV, an enlarged liver and/or spleen on ultrasound was present in 59%, whereas 63% had abnormal aminotransferases and/or gamma-GT values. In conclusion, 39% of the patients infected in childhood cleared HCV spontaneously. The majority of the patients with chronic hepatitis C had ultrasound and/or laboratory abnormalities and these findings may be associated with the presence of chronic liver disease.