Prior to the 1960s, little was known about morbidity and mortality in humans due to group B streptococcus (GBS). Since that time, a thorough understanding of the organism's potential has been developed. Of pregnant women, 20–30% are prenatal carriers of GBS and 40–75% of these mothers will transmit GBS to their neonates. However, the actual incidence of GBS disease in infants is one to three cases per 1,000 live births. Several risk factors for transmission and development of early-onset GBS disease have been identified. The understanding of late-onset disease is less clear. Many strategies have been investigated to find an optimal protocol to reduce significantly the incidence of GBS disease in a cost-effective manner. The Centers for Disease Control and Prevention have recently made recommendations for prevention strategies against this disease.