Herpes simplex virus is an important cause of neonatal infection, which can lead to death or long-term disabilities. Rarely in utero, the transmission frequently occurs during delivery. The disease may be disseminated, localized to the central nervous system, or involving skin, eye and/or mouth. Mortality rates markedly decreased with high-dose antiviral treatment. Diagnosis of neonatal infection is based on viral isolation from ulcerated vesicles or by scarifying mucocutaneous lesions. Recently polymerase chain reaction plays a central role for both viral detection (skin, mucosal, cerebrospinal fluid samples) and response to therapy. Vertical transmission may be decreased by prophylactic antiviral treatment.