Background. Group B streptococcus and premature rupture of membranes are independent risk factor for the development of both maternal and perinatal morbidity and mortality. Objective. To determine the prevalence of group B streptococcus, pregnancy outcome, antibiotics sensitivity and resistance pattern among pregnant women with preterm prelabour rupture of membrane. Design. A Case-control study comprising 50 cases of PPROM and 50 control. The control group comprised pregnant women similar in age, parity and gestational age without PPROM. Methods. Using a proforma, information on the socio-demographic data and obstetric profile were obtained from both cases and control. High vaginal swabs were done for both cases and control. Buccal, umbilical and skin swabs were also obtained from the neonates at birth.