Untreated infection may cause stillbirth by several mechanisms, including direct fetal infection, placental damage, and severe maternal illness. Many bacteria, viruses, and protozoa have been associated with stillbirth. In developed countries, up to 24% of stillbirths have been attributed to infection, although with increased availability of sophisticated diagnostics and rigorous screening, it appears likely that higher numbers may actually be associated with infection. In developed countries, ascending bacterial infection is usually the most common infectious cause of stillbirth, with a number of viral infections also an important factor. Screening, prevention, and treatment of maternal infections are important to reduce stillbirth risk.