Calcium gluconate is frequently administered after the end of cardiopulmonary bypass in order to produce moderate improvement in myoeardial contractility and performance. Numerous investigators found good correlation between the cardiac output measured by combined transesophageal Doppler cardiac output and thermodilution or Fick cardiac output. Transesophageal Doppler cardiac output monitoring was more reproducible, showing less short- term variability than thermodilution cardiac output. We researched the hemodynamic effects of l0, 20, and 30 mg/kg of calcium gluconate with transesophageal Doppler cardiac output in 30 valve replacement patients following cardiopulmo- nary bypass. The results were as follows; l) The mean arterial pressure was statistically increased for 5 minutes after 30 mg/kg injection of calcium gluconate, but there was no special changes after l0 and 20 mg/kg injection of calcium gluconate. We could not find profound bradycardia after calcium gluconate injection. 2) The cardiac index was statistically increased for 5 minutes after 30 mg/kg injection of calcium gluconate, but there were no changes in less doses. The systemic vascular resistance was decreased after calcium gluconate injection and more pronounced in 30 mg/kg injection of calcium gluconate. 3) Ionized calcium was most increased at 1 minute after calcium gluconate injection and specially about 50% rise at 1 minute after 30 mg/kg injection of calcium gluconate. After 1 minute, there was sharply decreased, not sustained. In conclusions it was available to administer 30 mg/kg of calcium gluconate for hemodynamic assistance following cardiopulmonary bypass. Calcium gluconate should probably not be routinely administered upon discontinuing cardiopulmonary bypass, but should be selectively used when needed to transiently augment myocardial contractility.