We report the results of prenatal diagnosis in 15 cases of primary cytomegalovirus infection during pregnancy. Sixteen fetuses (one twin pregnancy) were examined by ultrasonography, amniocentesis, and fetal blood sampling. Prenatal diagnosis was positive in eight cases as evidenced by positive amniotic fluid cultures in eight, positive immunoglobulin M (IgM) in six, and abnormal ultrasound in two. Among infected fetuses, abnormal laboratory findings included anemia, thrombocytopenia, and elevated liver function tests. Three pregnancies were terminated because of ultrasound abnormality or abnormal laboratory indices. In cases of fetal infection with normal ultrasound and normal laboratory findings, the pregnancies were allowed to proceed, leading to the birth of four infants (three with subclinical infections, one with bilateral hearing loss). The relation between anemia, thrombocytopenia, altered liver function tests, and subsequent handicap remains unknown, but the abnormalities observed in utero correspond to those described at birth in cases of cytomegalic inclusion disease. Amniocentesis alone allowed the diagnosis of infection in all cases, but fetal blood sampling provided additional information about the fetal condition.