Neonates, particularly when premature, are relatively immunocompromised and are therefore prone to more infections, more severe disease, and infection with unusual organisms. Almost all foetal and many neonatal infections are caused by organisms acquired from the mother. Transmission may be transplacental in utero, perinatal during the birth process or postnatal. Neonates can also acquire infections horizontally. This review provides an overview of the epidemiology, clinical features, diagnosis, prevention and treatment of infections in the foetus and neonate with updates on new developments including the identification of risk and management of maternal hepatitis B and HIV infections, the role of molecular diagnosis, new vaccines under development and the role of emerging infections. © 2009 Elsevier Ltd.