Preoperative echography of a saphenous vein graft (SVG) was studied. In 58 cases of consecutive coronary artery bypass grafting, 31 patients underwent SVG echography. Preoperative assessment revealed vein caliber, branching, or varicose saphenous veins. The location of the saphenous vein was marked. Saphenous veins were harvested by the open harvest technique, and the caliber of the veins and the availability of the anastomosis device were recorded. Postoperative morbidity was recorded. Preoperative findings revealed that four (6.5%) of 62 femoral saphenous veins were estimated as "not graftable" because of being a varicose vein or having a small caliber. Seven of 32 lower saphenous veins were estimated as "not graftable". The mean discrepancy of the caliber was 0.6 mm undersized with preoperative estimation. During harvesting, one of 31 patients had a wrong marking. We were able to use all harvested veins. The morbidity of saphenous harvesting was observed in two (6.5%) of 31 patients. One patient whose marking was wrong had minor skin necrosis. Another patient experienced a hematoma because of the excess effect of warfarin. Preoperative ultrasonic mapping of the saphenous vein reduced useless harvesting, provided information concerning anastomosis device availability, and seemed to reduce morbidity because dissection can be minimal.