From December 1981 to June 1987, thirty one patients suffering from low output syndrome after cardiac operation received cardiac assist with intraaortic balloon pump. Fifteen patients survived [survival rate 48.4%]. After receiving assist with IABP, urine output increased, heart rate and central venous pressure decreased, reflecting improved myocardial performance. Poor preoperative hemodynamic and functional status resulted in poor survival despite of assist with IABP. Poor pre-IABP hemodynamic status also resulted in high mortality after assist with IABP. Our experience suggests that IABP should be introduced early in the course of worsening to get good result.