A case of congenital absence of both aortic and pulmonary valves with severe heart failure detected prenatally by cross-sectional and pulsed and colour Doppler echocardiography is reported in small for gestational age male fetus in 17th week of gestation. Additional double outlet right ventricle, hypoplastic left ventricle, and ventricular septal defect, as well as multiple extracardiac anomalies, were found by prenatal echocardiographic investigation and confirmed by necropsy examination. Retrograde diastolic Doppler waveforms retrieved from pulmonary artery, aorta, and umbilical arteries revealed massive insufficiency throughout both the great arteries, which eliminated diastolic placental perfusion, documented by absent anterograde diastolic flow in the umbilical vein. These prenatal echocardiographic findings may contribute to an understanding of the mechanism of rapid and progressive heart failure and growth retardation in the fetus. Severe cardiac failure may explain why congenital aplasia of both the aortic and the pulmonary valves has not been described postnatally, and only two fetal cases revealed by necropsy have been published.