The one year results of three techniques of bypass grafting of the artery of the left border of the heart were compared in a retrospective study in 120 patients all undergoing left anterior descending bypass grafting with an internal mammary artery. Group I comprised 38 consecutive patients: the left border artery was bypassed with a venous graft. Group II comprised 49 consecutive patients who had the left border artery bypassed by an internal mammary artery in situ. Group III comprised 33 consecutive patients who had the left border artery bypassed by an internal mammary graft issuing from a Y-shaped construction (right internal mammary artery as a free graft reimplanted into the left internal mammary artery). The operative mortality, morbidity and functional results were comparable in the three groups. The rate of angiographic success of the left border artery graft at one year was: 65.7% in group I, 89.5% in group II and 87.8% in group III. The one year patency of internal mammary artery grafting of the artery of the left border was higher than that of venous grafts (p < 0.05).