From December 1975 to September 1989, nine children, ages 0.6-15.8 years (mean = 8.1 years) and weighing 5-44 kg (mean = 24 kg), were identified as requiring intraaortic balloon pump support. Indications included ventricular failure refractory to maximal conventional therapy, inability to wean from cardiopulmonary bypass, and myocardial ischemia. Prior to insertion of the balloon catheter, mean systolic blood pressure was 64 mmHg, one to four cardiotonic medications were being administered, mechanical ventilation was being performed in eight patients, and mean urine output was 0.4 ml/kg/min in eight. Following balloon catheter insertion, mean urine output increased to 0.9 ml/kg/min. Four patients survived following discontinuation of the balloon catheter 12-96 h (mean = 59 h) after initiation. Though complications such as loss of distal lower extremity pulses, sepsis, thrombocytopenia, and abdominal distention were observed, most could be attributed to other causes. Thus, the intraaortic balloon pump is a valuable addition to conventional medical therapy in the treatment of refractory cardiogenic shock in children.