The prevalence of persistent hepatitis-B surface (HBS) antigenaemia and hepatic functions have been determined in 125 children with sickle cell disease (SCD) as well as in 100 age-matched healthy children. Hepatic functions and the presence of HBS antigenaemia have been followed for 1 year in six children with SCD and 10 normal children following acute hepatitis-B infection. The prevalence of chronic HBS antigenaemia (3 per cent) in children with SCD is not higher than in normal children (11 per cent). The significant elevation of serum alanine transferase (ALT) and bilirubin concentrations in sickle cell children denotes a process of mild hepatocellular dysfunction which is unrelated to hepatitis-B viral antigenaemia. The high incidence of chronic HBS antigenaemia accompanied by elevated serum ALT and bilirubin concentrations in sickle cell children following acute hepatitis-B infection, in addition to the significant impairment of hepatic functions in sicklers with chronic HBS antigenaemia compared to those without the antigenaemia, point out to the high risk of continual parenchymal hepatic damage in these children following acute hepatitis-B infection. Vaccination against hepatitis-B virus should eliminate this risk.