Group B streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis in developed countries. This article reviews the neonatal invasive GBS disease, maternal GBS colonization, and prevention strategies in the context of recent epidemiological changes in Korea. Although Korean neonates had been supposed to have low incidence of invasive GBS disease, GBS has been recently reported to be the most common cause of invasive neonatal infection after 1990s. Among Korean pregnant women, GBS carriage rate in the vagina and rectum has been reported to be much lower than that in Western countries. However, it has increased in recent studies. For decision making about preventive strategy for neonatal GBS disease in Korea, further studies are required in terms of the incidence of neonatal GBS infection and serotype distribution. In addition, studies about maternal carriage rate and serotype distribution have to be continued.