During the period 1966-76, 164 patients with pneumococcal meningitis were admitted to the University Hospital, Copenhagen. Of 111 survivors 94 underwent a series of clinical examinations. The findings in each patient were assessed for their aetiological relationship to meningitis. Of these patients 54% had neurological sequelae, 42% had neuropsychological sequelae, 25% had otological sequelae and 16% had sequelae as judged by computer-assisted tomography of the brain. On the basis of the general clinical condition, each patient was evaluated for the presence of sequelae of meningitis by means of a rating of nil, mild, moderate or severe. These ratings and mortality rates were used to evaluate the prognostic significance of various features present during the acute illness. A fatal outcome was significantly associated with increasing age, concomitant pneumonia, altered consciousness on admission, transfer from another hospital and development of complications while in hospital. There was a statistically significant association between lasting sequelae and the female sex, the age group of 16-50 years, patients who had not received any pre-admission antibiotic therapy and those with positive bacterial cultures of specimens from sites other than blood or cerebrospinal fluid.