Background: In patients with chronic hepatitis C (CHC), superinfection with hepatitis A (HAV) or B (HAB) viruses is associated with increased morbidity and mortality. The seroconversion rate of these patients following vaccination is considered to be lower than in healthy subjects.Aim: To evaluate the response to HAV and HBV vaccination in children with CHC.Methods: Thirty patients with CHC aged from 7·3 to 18 years were compared with 50 healthy age-, gender- and body-mass-index-matched controls. Post-vaccination serological evaluation was performed 1 month after the last dose of primary vaccination, 1 month after the booster dose and once a year during follow-up.Results: Twenty-two patients received hepatitis A vaccine and response rate was 95·4%. Thirty patients received hepatitis B vaccine and 80% responded (hepatitis Bs titres ⩾10 mIU/ml). Thirty-five controls received hepatitis A vaccine and protective anti-HAV antibodies developed in all. All of the controls were vaccinated against hepatitis B virus and 90% responded. After the whole vaccination series, overall seroprotection rates were 86% in patients and 96% in controls. No significant reduction in antibody response was observed in patients or controls during 8-years follow-up.Conclusions: The rate of seroconversion to the HBV vaccine is lower in patients with CHC than in healthy controls but response to HAV is adequate.