A case of lithium intoxication in the newborn is presented. Besides displaying extreme hypotonia and a goitre, the infant developed symptoms of congenital heart disease immediately after birth. Cardiac catheterization and angiocardiography revealed an elevated pulmonary vascular resistance and indicated that the cardiopulmonary symptoms were caused by persistent fetal circulation. Previously, four authors have independently reported cardiopulmonary symptoms in association with lithium intoxication without finding cardiac or pulmonary disease. The similarity between the present and the four earlier reported cases in regard to the symptoms and the course of illness, raises the question of the connection between lithium intoxication and persistent fetal circulation being more than coincidental. In view of recent investigations it is speculated that lithium intoxication in utero may result in the pulmonary vascular changes responsible for the persistence of fetal circulation.