Neonates, especially those in a neonatal intensive care unit, are at high risk for infection. Colonized neonates are a major source of infection, and microorganisms can easily be transmitted between neonates on hands or equipment. Other sources include contaminated patient care supplies, infected personnel, family, and other visitors. The risk increases with decreased birth weight and/or gestational age and with exposure to invasive procedures and indwelling devices. In the newborn nursery, infections of the skin, mouth, and eye are most frequent; in the neonatal intensive care unit, bloodstream infections predominate. Coagulase-negative Staphylococcus, Staphylococcus aureus, Enterococcus, Enterobacteriaceae, and Candidaare most frequently isolated. Methicillin-resistant Staphylococcus aureusis a significant presence in the neonatal intensive care unit. Outbreaks of respiratory and gastrointestinal viral infections also occur. This chapter presents the essential elements of infection prevention in the neonate environment.