Purpose : The purpose of this study is to confirm the epidemiologic change of the causative organisms of neonatal and pediatric bacterial meningitis in Korea. And we tried to evaluate the risk factors correlated with prognosis which was available on the day of admission. Methods : Retrospectively, we reviewed the medical records of 57 patients admitted for bacterial meningitis at six hospitals affiliated with Catholic Medical Center for 6 years(Jan. 2000~Dec. 2005). Results : 22 cases(38.6%) of them were neonates under 28 days and 35 cases were infants and children ; 16 cases(28.1%), under 1 year ; 6 cases(10.5%), under 5 years ; 13 cases (22.8%), under 15 years. In neonates, 16 cases(72.7%) were caused by group B streptococcus (GBS). In infants and children, S. pneumoniae(25.7%), H. influenzae type b(Hib)(22.8%) and N. meningitidis(22.8%) were common cause of bacterial meningitis in order. In the informations available on the day of admission, weight deficit for age under 3 percentile, increased CRP level and decreased glucose level of CSF were related to poor prognosis(P<0.05). Conclusion : GBS became a leading cause of neonatal bacterial meningitis. Though, pneumoccocal, Hib and meningococcal meningitis were confirmed as major causes of bacterial meningitis. The routine immunization of pneumococcal and Hib vaccines will be considered, and it is necessary to introduce meningococcal vaccines to our country in the future.