Group B streptococcus is known to be a leading cause of neonatal infection, but less appreciated is the fact that it causes maternal infection also. Maternal group B streptococcal infections during pregnancy and delivery threaten not only the mother, but the child as well. Postpartum infection, such as mastitis, bacteremia, sepsis, meningitis, endometritis, and wound infections are hazards to the mother. We describe the various maternal group B streptococcal infections, their characteristics, associated neonatal morbidity, and prevention and treatment strategies during pregnancy, delivery, and in the postpartum period.