Group B streptococcus (GBS) is the leading etiologic agent of bacterial meningitis and sepsis during the neonatal period, but it is an infrequent cause of meningitis in adults. We report 12 episodes of group B streptococcal meningitis in adults and review 52 cases reported in the literature. A total of 24 men and 40 women were included in the study; the mean age (+/- SD) was 49.2 +/- 20.5 years (range, 17-89 years). All the patients had cerebrospinal fluid cultures positive for GBS. Eighty-six percent of the patients had comorbid conditions, 50% had a distant focus of infection, and blood cultures yielded GBS for 78.7%. The overall case-fatality rate was 34.4% (22 patients). Factors associated with a poor outcome were advanced mean age (+/- SD) (61.5 +/- 17.4 years vs. 42.8 +/- 19.2 years; P = .0003) and the presence of complications on admission (P = .0001). Seven percent of survivors had neurological sequelae. Group B streptococcal meningitis in adults has become increasingly frequent in recent years; it tends to occur in patients with severe underlying conditions and is associated with a high case-fatality rate. Factors associated with a poor prognosis are advanced age and the occurrence of neurological and extraneurological complications.