90 cases of invasive pneumococcal infection hospitalized during the period 1975-1984 were reviewed. The organism was recovered from blood, cerebrospinal fluid or other normally sterile body fluids. 40 of the patients were adults, most of whom had pneumonia, and 50 were children who had pneumonia, primary bacteremia or meningitis. 90 % of the adults and 14% of the children had underlying conditions. Nosocomial infection was remarkably more common among adults (25 % than among children (2 % Mortality was similar to that reported by others: 37 % for adults and 10 % for children. The most important predictive factors for fatal outcome were: old age (<80), meningeal infection, presence of malignancy or chronic lung disease, and failure to mount leucocytosis. 13 % of the strains were moderately resistant to penicillin.