Radial artery conduits have recently been used more often in coronary artery bypass grafting because of their potentially better long-term patency than saphenous vein conduits. However, vasospasm of the radial artery conduit due to its nature as a muscular artery has always been of concern and a variety of vasodilators have empirically been used to reduce the risk of spasm. When a patient who was preoperatively taking antihypertensive agents undergoes coronary artery bypass using a radial artery graft, and if he/she is not hypertensive postoperatively, it is not always easy to decide what medication to start with. We report a case of a patient with a radial artery graft who did not receive vasodilators after surgery due to hypotension. The patient developed vasospasm of the radial artery conduit which did not respond to direct injection of vasodilators into the conduit but recovered after taking oral vasodilators for four weeks.