BACKGROUND Maternal Group B Streptococcus (GBS) vaginal and rectal carriage is an established risk to both the pregnant woman, the fetus and the neonate. However, it has not received adequate attention especially in developing countries where most health facility protocol for screening and prevention of its vertical transmission is unavailable. OBJECTIVES To establish maternal vaginal and rectal group B Streptococcus carriage rate, determine risk factors for colonization, associated perinatal events, evaluate a vertical transmission prevention effort as well as to establish the antibiotic sensitivity and effectiveness among GBS carriers in pregnant women attending antenatal care at University Of Ilorin Teaching Hospital (UITH), Ilorin. METHODOLOGY A hospital-based cross-sectional study involving consenting booked pregnant women at 35-37 weeks gestational age at the study site. All participants had lower vaginal and rectal swabs taken for culture and antibiotic sensitivity test optimized for GBS with availability of culture results before the onset of labour. All GBS carriers had intrapartum parenteral antibiotics, administered base on the sensitivity results. Mothers were evaluated for puerperal complications, while neonatal follow-up for neonatal sepsis lasted for seven days.