Streptococcus pneumoniae isolates resistant to penicillin and other antibiotics have been increasing in many parts of the world. The aim of this study was to evaluate the antimicrobial susceptibilities to penicillin and other commonly used agents in 98 isolates recovered between 1997 and 1998 from clinical specimens from children, and to determine the serotypes/serogroups related to resistance. Susceptibility to penicillin was determined by E-test and disk diffusion tests were used for the other antimicrobials. Serotyping was performed on all the isolates by the quelling reaction. The rates of intermediate- and high-level resistance to penicillin were 29.6% and 2%, respectively. Overall resistance to trimethoprim-sulfamethoxazole was high (46%), of which 21% coexisted with penicillin resistance. Resistance rates to erythromycin and chloramphenicol were 5% and 1%, respectively. Five isolates were multi-drug resistant. The most frequent serotypes associated with penicillin resistance were serotypes 19, 23, 6, 9 and 15.