We evaluated the effects of colforsin daropate hydrochloride (CDH) after cardiopulmonary bypass (CPB) in comparison with milrinone. CDH or milrinone were given during and after CPB combined with cathecholamines so as to maintain mean arterial pressure (mABP > 60 mmHg) and cardiac index (CI > 3.0 l.min-1.m-2). Hemodynamics measurement was done immediately after CPB (A 1), one hour after CPB (A 2) and after the chest closure (A 3). In CDH group, mABP was significantly higher compared with milrinone group. Also, CDH group showed a significant reduction in the cases of combined use of dobutamine (at A 2, A 3) and norepinephrine (at A 1, A 2) compared with milrinone group. In conclusion, colforsin daropate hydrochloride exerts more inotropic effect and could reduce the necessity of combined use of cathecholamine compared with milrinone.