In 67 splenectomized children vaccinated with a 14-valent pneumococcal capsular polysaccharide vaccine an antibody fold increase above 2 from pre- to postvaccination samples was found in 60% of all single type antibody determinations performed. The vaccine may only afford protection against 55% of those serotypes that cause serious infections in children, assuming a protective antibody level of 300 ng antibody N/ml. Our results indicate a somewhat reduced antibody response to pneumococcal vaccine in splenectomized children and suggest that pneumococcal vaccination may not be relied upon as the only kind of prophylaxis against pneumococcal infection in this patient group.