A 57 year-old man with angina pectoris was transferred to our hospital for coronary artery bypass grafting. His past history was schizophrenia and paroxysmal atrial fibrillation. He had been taking major tranquilizers for 20 years. Off-pump coronary artery bypass grafting (RITA-LAD, LITA-OM-D2, Ao-SVG-#4PD-#14PL) and bilateral pulmonary vein isolation was performed. During the distal anastomosis, systolic blood pressure was decreased and bolus infusion of norepinephrine and phenylephrine were not effective. Vasopressin was injected (1U/shot), and stabilized his hemodynamic status without any mechanical support. After the operation, vasopressin was continued to postoperative day (POD) 4. There was no side effect related to vasopressin. He was discharged from the hospital on POD 12. When major tranquilizers are taken for a long time patients can be resistant, or overreact to catecholamine. Vasopressin can be a valid option as a vasopressor for such catecholamine refractory hypotension.