Tetralogy of Fallot with absence of the leaflets of the pulmonic valve is relatively rare. We describe the prenatal diagnosis of this malformation in two fetuses. The association between the agenesis of the arterial duct and absence of the valvar leaflets is discussed. The diagnosis of the syndrome in the presence of dilated and pulsatile pulmonic arteries is easy to make. It should allow early counselling and planning of early care after delivery.