Aims. The aim of this study was to compare coronary artery bypass grafting (CABG) using either endoscopic (EVH) or open harvest (OVH). Leg-related morbidity and histological comparison of the veins were the outcome measures. Methods. One hundred consecutive patients scheduled for isolated CABG were randomly divided into two goups: an EVH and OVH group. Perioperative data were recorded. Patients were examined 7 days and 1 month postoperatively for leg-related morbidity. Samples for histological examination were taken from each harvested vein during the surgery. Results. Postoperative pain was statistically significantly lower in the EVH group 7 days postoperatively but the incidence of haematoma was non statistically higher in the EVH group while swelling was higher in the OVH group. Almost 40% of all histological samples were described as showing endothelial damage. There was significantly more endothelial damage in the EVH than the OVH group. Conclusions. We confirmed the advantage of EVH in terms of leg-related morbidity as well as cosmetic effect. This method however, was associated with more acute endothelial damage of the graft. These results support concerns that endoscopic vein harvest may be connected with detrimental effects on vein endothelium which could promote a thrombogenic environment leading to a decrease in graft patency. This could be extremely important. The results suggest that further investigation of the long-term patency of vein grafts harvested endoscopically is required.