We evaluated a screening program for the detection of congenital cytomegalovirus in 3075 unselected pregnant women. From each live-born child urine for CMV culture was collected within 7 days after birth. Each fetus expelled after a spontaneous second trimester abortion and each stillborn infant were also evaluated for a possible congenital CMV infection. For each congenital infection stored maternal sera were analysed to determine whether maternal infection was primary or recurrent. Fifteen out of the 3075 pregnancies studied resulted in a congenitally infected infant (0.49%). Nine maternal CMV infections were primary infections; five were recurrent infections, and in one case the type of infection could not be determined. Three congenital infections resulted in severe sequelae, leading to the termination of pregnancy in two instances and to neonatal death in one case. One of these severe fetal infections was due to a recurrent maternal infection. Follow-up of the other 12 neonates demonstrated hearing disorders in two children. One was born after a primary maternal infection and one after a recurrent maternal infection. We conclude that congenital CMV infections occurs in 0.49% of all pregnancies in the population studied. Twenty percent of the congenitally infected infants present severe sequelae at birth or during pregnancy, and an additional 17% have audiological deficits at 1 year of age. Severe sequelae may occur after both primary and recurrent maternal CMV infection.