A new single chambered percutaneous intraaortic balloon has been constructed around a central guidewire. The balloon can be wrapped around the guidewire, enabling its insertion into the femoral artery through a 12F sheath inserted with the conventional Seldinger technique. Percutaneous intraaortic balloon insertion has been performed in 27 patients (mean age 58 years) for a variety of medical and surgical indications. Percutaneous balloons could not be advanced into the aorta in two patients (7.4 percent) with severe bilateral aortoiliac occlusive disease. In all 25 patients undergoing intraaortic balloon pumping satisfactory circulatory support was achieved, and 21 (84 percent) of the patients survived to be discharged from the hospital. The mean duration of intraaortic balloon pumping was 3.5 days. Percutaneous intraaortic balloon insertion requires less than 5 minutes and has been successfully performed in the cardiac catheterization laboratory, coronary care unit, operating room and recovery room. After direct balloon removal, external pressure was applied for 30 minutes. No patient experienced hematoma of the groin, aortic dissection, compromised distal pulses or late wound complications. Percutaneous balloon insertion permits the rapid institution of circulatory support and broadens the medical and surgical applications of intraaortic balloon pumping.