Levosimendan (LS) is a novel calcium sensitizer drug that enhances cardiac contractility without increasing myocardial oxygen consumption, and induces vasodilatation. Positive inotropic support is routinely used for weaning from cardiopulmonary bypass circulation in patients with reduced left ventricular function. This case report represents the successful usage of LS for weaning from cardiopulmonary bypass circulation after coronary artery bypass surgery. Levosimendan infusion was started at the sixth hour of cardiopulmonary bypass circulation. There was a dramatic increase in cardiac output 20 minutes after LS infusion, and weaning from cardiopulmonary bypass circulation was achieved. We suggest that LS enhances cardiac performance during and after cardiopulmonary bypass, and can be useful for patients who are unable to be weaned from cardiopulmonary bypass.