Introduction: The composition of the human vaginal microbiota may be influenced by hygiene practices, age, infections, sexual activity and hormonal changes e.g. pregnancy.  Aerobic vaginitis (AV) refers to a disruption of the normal vaginal microbiota accompanied by an increase in vaginal pH and inflammation. Aerobic bacteria commonly associated with AV include GBS, known to be associated with adverse pregnancy outcomes and neonatal morbidity. GBS serotypes have been reported to differ in pathogenicity amongst women with different geographical location.  The objective of this study was to establish the serotype prevalence in a cohort of pregnant South African women. Materials and methods: Ethics clearance for the study was obtained and 301 mothers gave informed consent to participate in the study.  High vaginal swabs were collected by a clinician and GBS isolation confirmed by standard procedures. Serotyping was achieved by the use of Streptococcus Group B typing sera SSI-LATX-54985/7, Denmark). Results: Six different serotypes were identified, with serotype V predominating (66.7%), followed by serotype III (21.1%). One isolate from each of serotypes Ia, II,IV and IX were found. Serotype V showed antimicrobial resistance to several antibiotics used in prophylaxis. Conclusion: The colonisation of resistant GBS serotypes during pregnancy could pose a risk for maternal and neonatal morbidity in this population.