In coronary artery bypass grafting, saphenous veins are widely used as a composite grafts that are Y-anastomosed to in-situ left internal thoracic artery. Based on our observation that remodeling of saphenous vein graft differs between those harvested from upper leg vein and lower leg, this study aims to compare histologic and immunohistochemical findings between saphenous vein grafts harvested from upper leg and lower leg.