BACKGROUND: Beta-hemolytic streptococci (BHS) are frequently isolated pathogens in the clinical microbiology laboratory, and the isolation frequency of each serogroup of BHS are influenced by patient type, nation and region, study period, and investigators. The aim of this study is to investigate the isolation rates and distribution of BHS by serogroup at Wonju area during the recent periods. METHODS: Isolation rates of BHS isolated from 1997 to 2000 at Wonju Christian Hospital were investigated. The distribution of each serogroup of BHS according to the types of clinical specimens was also studied. Serogroups A, B, C, F, and G were determined by latex agglutination test (Murex Streptex kit). RESULTS: Of 627 BHS isolated during the study periods, 16.3% were group A, 49.3% were group B, 5.1% were group C, 4.3% were group F, 21.0% were group G, and 4.0% were nongroupable. Isolation rates of BHS by specimen type were as follows:wound/pus was 44.4%; cervix, urine, and respiratory specimen ranged from 10% to 20%; blood was 4.0%; body fluid was 2.9%; and cerebrospinal fluid was 0.5%. The prevalent isolation sites by serogroup were:group A, wound/ pus (78.4%); group B, cervix (32.7%), urine (28.5%), and wound/pus (26.2%); group C and G, wound/pus and respiratory specimen; and group F, wound/pus and urine. From blood, group B streptococci (44.0%) were the most frequent isolate. CONCLUSIONS: Half of BHS isolated from clinical specimens were group B streptococci in this study, which reflects the increasing trend of group B streptococcal infections during the recent years at Wonju area.