Abstract: AIM:To evaluate the hemodynamic effects of vasopressin in patients with vasodilator shock after cardiac operation. METHODS: A retrospective review was conducted and compared in 32 cases of infants who underwent complex cardiac operation from June 2010 to October 2012 and were treated with early use of small doses of AVP postoperatively and 35 cases of infants who underwent the same operation from August 2008 to May 2010 but were treated with early use of norepinephrine postoperatively. RESULTS: No significant difference was found between groups in basic data, heart rate, blood pressure, central venous pressure, maximum lactate value, minimum of ScvO2, Pcv-aCO2, urine volume and chest drainage. However, in AVP group, the vasoactive drug score and rate of arrhythmia were lower, and the time of mechanical ventilation and length of stay in ICU was reduced. CONCLUSION: AVP improves postoperative hemodynamics in patients suffering from vasodilator shock after cardiopulmonary bypass.