Disseminated herpetic infection occurred in a newborn infant girl, delivered by cesarean section, who survived after a stormy course. The source of her infection was found to be her mother who had a lesion of the cervix resembling invasive cervical carcinoma. Viral and serological studies confirmed the presence in both mother and infant of a primary infection with herpes simplex virus. The genital tract of mothers of infants with suspected herpetic infection should be studied carefully to ascertain a likely source of neonatal infection. Cesarean section should be considered in pregnant women with primary herpetic genital infections close to delivery, particularly if the membranes are still intact.