Chronic maternal toxoplasmosis is an established cause of congenital infection in animals. The association between preconception infection with Toxoplasma and human abortion is not established. Chronic maternal toxoplasmosis leading to congenital infection has been reported in immune competent and immune compromised individuals but the incidence is not known. Limited studies suggest that toxoplasmosis may pass from the immune competent, chronically infected mother to the fetus in 0–6% of pregnancies. Maternal HIV infection may result in increasing numbers of children with congenital toxoplasmosis.