Herpes simplex virus infections of humans have been known since ancient times. Contemporary society has witnessed a series of devastating manifestations of herpes simplex virus infections-namely, genital herpes simplex virus infection and neonatal herpes simplex virus infection. With the evolution of society, particularly advances in birth control and increasing promiscuity, the seroprevalence of herpes simplex virus type 2 infections has increased worldwide, however, more so in developed societies. As a consequence, individuals of child-bearing age are at risk for either reactivation of herpes simplex virus at termination of gestation or acquisition of a new primary infection at that time. The consequences of vertical transmission of herpes simplex virus from mother to child, resulting in neonatal herpes simplex virus infection, can be devastating. Current efforts, which are directed toward the treatment of neonatal herpes, have established the value of drugs such as vidarabine and acyclovir. However, the real emphasis for future programs is the prevention of herpes simplex virus infections to avoid person-to-person transmission either horizontally or vertically. The development of vaccines directed against herpes simplex virus may be of value toward this end.