In a series of 1600 pregnancies 34 cases of congenital heart disease were correctly identified by fetal echocardiography. In each case echocardiographic diagnosis was confirmed by anatomical study. Termination of pregnancy was done electively in 14 cases: in six because of the identification of a cardiac anomaly and in the remaining eight because of multiple congenital anomalies. The remaining 20 fetuses died subsequently owing either to the complexity of congenital heart disease or to associated extracardiac abnormalities, which were present in more than half the fetuses with congenital heart disease. There were eight errors in interpretation of the fetal echocardiogram. The outcome of the pregnancy was not influenced by the error in any case. Fetal echocardiography can predict correctly structural malformations of the heart. The technique is sufficiently reliable to give an accurate prognosis in early pregnancy and provide the basis for alterations in obstetric management.