We previously conducted nationwide surveillance of Streptococcus pneumoniae in 2000-2001 (period 1) and 2004 (period 2) and reported the findings. Subsequent surveillance surveys conducted in 2007 (period 3) and 2010 (period 4) are now reported. Bacterial strains were clinically isolated from children with meningitis, sepsis, and respiratory tract infections at 27 hospitals participating in the Drug-Resistant Pathogen Surveillance Group in Pediatric Infectious Disease. Twenty-one drugs were investigated for 283 isolated strains in period 3, and 24 drugs were investigated for 459 strains in period 4. In period 3, 43.8 % of strains were penicillin-susceptible S. pneumoniae (PSSP), 52.3 % were penicillin-intermediate S. pneumoniae (PISP), and 3.9 % were penicillin-resistant S. pneumoniae (PRSP). In period 4, the percentages were PSSP 23.1 %, PISP 49.9 %, and PRSP 27.0 %. The resistance rates were 56.2 % and 76.9 %, respectively. Drug sensitivity was best with panipenem, at a minimum inhibitory concentration (MIC)90 ≤0.063 μg/ml in period 3, and with tebipenem (MIC90 ≤ 0.063 μg/ml) in period 4. Patients' background factors related to increased bacterial resistance were investigated, and significant differences were found depending on whether a child had siblings (P = 0.0056) or was a daycare center attendee (P = 0.0195) in period 3, and age category (P = 0.0256) in period 4. No factors were common to both periods 3 and 4. Pneumococcus is a major causative organism of pediatric infectious disease, and we plan to continue conducting surveillance and providing information in the future.