An epidemiologic study on vaginal colonization of group B streptococcus (GBS) from non-pregnancy women was carried out. Two hundred sixty seven female workers were studied. The carrier rate of GBS in vaginal specimens was 10.86%. Women aged 45 years old and above had more cases with genital tract GBS colonization. Women with vaginal colonization had more history of miscarriage and using IUD. We did not find the positive correlations between vaginal colonization and oral contraceptive, ovarian cyst, hysteromyoma in our study group. Women with gynecologic inflammation had more cases with vaginal GBS colonization. There is a significant increase for women with vaginitis and cervicitis. Serotyping study showed that types III and II were the most frequent GBS types isolated from the carriers. Antibiotic sensitivity test showed that more than half GBS strains were resistant to oxcillin and amikacin.