Pneumococcal sepsis is a life-threatening complication in splenectomised patients even since the introduction of a polyvalent pneumococcal vaccine. Eight episodes of pneumococcal sepsis in seven properly vaccinated splenectomised patients are described. All but two of the causative serotypes were included in the vaccine. The fact that most of the patients were immunosuppressed may explain the failure of the vaccine in these particular patients. A survey of 59 episodes of pneumococcal bacteraemia during 1982 at the Soroka Medical Center, however, shows that 32 % of the strains of pneumococci isolated were among seven types not included in the vaccine. The addition of continuous antibiotic prophylaxis in vaccinated and splenectomised patients is suggested.