Summary.As a consequence of recent outbreaks of HAV infection by blood products, 91 patients, haemophiliacs and subjects with bleeding disorders (10 of whom were also anti‐HIV positive) susceptible to HAV infection received a formalin‐inactivated hepatitis A vaccine (HAVRIX 720 Elisa Units, SmithKline Beecham). Subcutaneous injections were given in the deltoid region at 0, 1 and 6 months. The seroconversion rates and litres, expressed in GMT IU/1, were determined at 1, 2, 6, 7, 12, 18 and 24 months. No adverse reactions to the vaccine were observed. The highest percentage of responders observed was 98.7% in anti‐HIV negative and 71.4% in anti‐HIV positive patients. The anti‐HAV GMT titres were higher in anti‐HIV negative than in anti‐HIV positive patients. The inactivated hepatitis A vaccine is safe, clinically well tolerated, and provides long‐term protection agains