Recently, isolation of penicillin-resistant S. pneumoniae has been increasing. The first Japanese case of penicillin-resistant pneumococcal meningitis was reported in 1988. We experienced a case of a one-year-old boy with penicillin-resistant pneumococcal meningitis who dead on arrival on his third day of illness. Minimal inhibitory concentration (MIC) of penicillin G or S. pneumoniae isolated from cerebrospinal fluid and blood was 0.6 micrograms/ml. We evaluated the antibiotic susceptibility of 163 strains of S. pneumoniae isolated from children from 1985 to 1988. Penicillin G (PCG), ampicillin (ABPC), cefotaxime (CTX), imipenem (IPM), and vancomycin (VCM) had good susceptibilities to S. pneumoniae. Twelve of the 163 isolates (7.3%) were penicillin-resistant strains whose MIC of PCG were more than 0.1 microgram/ml, and all of them were intermediately resistant. The annual penicillin-resistant rates were 12.5% in 1985, 1.3% in 1986, 0% in 1986, and 19.0% in 1988. We also evaluated the MIC distribution and MIC90 of antibiotics available for meningitis against penicillin-sensitive and -resistant S. pneumoniae. MIC90 of PCG and ABPC against penicillin-resistant strains was 1.56 micrograms/ml, and it might be dangerous to use PCG or ABPC for central nervous system pneumococcal infections. MIC90 of IPM against penicillin-resistant strains was 0.1 microgram/ml, and that of VCM was 0.4 micrograms/ml. There was little fall of susceptibilities of resistant strains in IPM and VCM. We evaluated the MIC distribution and MIC70 of antibiotics for oral usage against penicillin-sensitive and -resistant S. pneumoniae. Although there were falls of susceptibilities of resistant strains in PCG and ABPC, these two antibiotics had the best susceptibilities among the oral antibiotics.