Background: When internal thoracic artery (ITA) and saphenous vein graft are anastomosed to the same coronary artery, the patency rate of the internal thoracic artery graft with relatively narrow diameter may be decreased owing to competition of pressure and flow rate. We evaluate the clinical outcome and the patency of the ITA graft in patients undergoing dual grafting to the same coronary artery. Material and Method: In 14 patients with the ITA graft having relatively low flow, the ITA and saphenous vein graft were anastomosed to the same coronary artery. During the mean follow-up period of 33.5 months, coronary angiography was performed in 6 patients who complained of recurrent angina, needed confirmation of graft flow, or showed postoperative Q wave. Result: In all 6 patients, the ITA and saphenous vein grafts were patent without stenosis or obstruction. Two patients showed good flow in both grafts, 2 showed competitive flow in the ITA graft, and the remaining 2 showed poor flow in the ITA graft. Conclusion: Early operative closure When saphenous vein grafting was added to the same coronary artery that the internal thoracic artery was anastomosed to, the perfusion to the coronary artery was satisfied and the dual grafting did not affect the short-term and mid-term patency rate of the ITA.