The study describes 156 consecutive cases of pneumococcal bacteraemia among patients admitted to Hvidovre Hospital during the five-year period 1986-1990. Pneumococcal bacteraemia was most common in the age groups 0-4 and 50-99 years. The most common focus of infection was the lungs (84%). 81% had preexisting diseases and the most common were: Immunosuppression due to drugs, alcoholism, cardiovascular disease, chronic obstructive lung disease, diabetes and myelomatosis. Patients over 65 years of age had a higher case fatality (35%) than younger (12%). The overall case fatality rate was 24%. Twenty-three percent of cases were hospital-acquired, and associated with a case fatality of 37%. Pneumococcal bacteraemia was most common during the winter season and unrelated to influenza. Eighty-four percent of the examined isolates represented capsular types included in the 23-valent pneumococcal vaccine. Three percent of the tested strains were relatively resistant to penicillin (MIC > 0.1 microgram/ml). Despite antibiotic treatment, the mortality from pneumococcal bacteraemia, particularly in elderly, remains high. With this in mind, one may consider offering pneumococcal vaccination to persons over 65 years of age with chronic predisposing diseases.