A persistent left superior vena cava draining into the coronary sinus is the most benign and widely encountered abnormality and can easily be explained embryologically as the persistence of the usual pattern of vnous circulation in the embryo,. However a persistent left superior vena cava draining into the left atrium with absent right superior vena cava is an extremely rare anomaly. We report this situation in an infant with tetralogy of Fallot. The most common approach has traditionally been intraatrial baffle repair to create a tunnel to the right atrium or rerouting of the left superior vena cava flow by directly anastomosing the left superior vena cava to the right atrium In the present study the left superior vena cava was transposed to the left pulmonary artery after the correction of tetralogy of Fallot. The most common approach has traditionally been intraatrial baffle repair to create a tunnel to the right atrium or rerouting of the left superior vena cava flow by directly anastomosing the left superior vena cava to the right atrium. In the present study the left superior vena cava was transposed to the left pulmonary artery after the correction of tetralogy of Fallot.