Dynamic narrowing of native coronary vessels is widely known to occur during the systolic phase of the cardiac cycle. This phenomenon has also been reported to occur in coronary artery bypass grafts. However, to the best of our knowledge, only one case report exists of this event taking place in bypass grafts during diastole. We discuss the angiographic findings of a 73-year-old male who had undergone coronary artery bypass grafting surgery twice and experienced diastolic compression of his saphenous vein graft to the right posterior descending artery.