The mechanical extrathoracic "Berlin Heart" cardiac assist device was used for left ventricular support in an 8-year-old child of 27 kg body weight. Terminal left ventricular failure and life-threatening ventricular tachyarrhythmias in this child were sequelae of coarctation of the aorta, aortic stenosis and resultant severe left ventricular dilatation, hypokinesia and fibrosis. With the assist device, cardiogenic shock could be reversed. The child was extubated and mobilized during an 8-day waiting period for orthotopic heart transplantation. This case illustrates that the use of ventricular assist devices can be successfully extended to children and may be advantageous compared to other techniques of mechanical circulatory support, such as balloon pumping or extracorporeal membrane oxygenation.