TandemHeart, an adult ventricular assist device, is also being used in children for mechanical circulatory support. In this case series, we describe our experience using TandemHeart ventricular assist device with a modified circuit to provide mechanical circulatory support in three neonates for multiple indications. TandemHeart ventricular assist device with a modified circuit can be used successfully to provide extracorporeal support to neonates with complex CHD.