During the 10-year period ending in July 1960, 43 patients with pneumococcal meningitis were encountered. The majority were over 50 years of age. Meningitis was secondary to pneumonia in 17 patients and to otitis media in 8. The spinal fluid smear was very reliable for early diagnosis, revealing the etiologic organism in 30 of 31 instances. Factors having a bearing on prognosis were evaluated: the presence of associated pneumococcal infections, illness of over 3 days duration and coma were associated with a mortality of 75% or greater. Bacteremia, old age, blood count, spinal fluid cell count or sugar concentration did not correlate with mortality. Therapy in 36 patients was broadly classifiable into penicillin alone (23 patients), erythromycin (6 patients) and penicillin and one of the tetracycline group (7 patients)''. The mortality in the penicillin-treated group was 56%, that of the erythromycin group 50%, and 85% in the group treated with penicillin and a tetracycline.