A 77-year-old man presented with chest discomfort on exertion for several weeks. Thirty-one years prior, he had performed on-pump coronary artery bypass grafting (CABG) using the pedicled left internal thoracic artery (LITA) to left anterior descending artery (LAD) and saphenous vein grafts (SVGs). The SVGs to the left circumflex artery had already occluded and to the right coronary artery (RCA) had previously required percutaneous coronary intervention (PCI). Although an electrocardiogram showed no remarkable change and echocardiography showed findings of known old posterior myocardial infarction, single-photon emission computed tomography demonstrated new inferior myocardial ischemia. Coronary angiography showed occlusion of all native coronary artery and severe stenosis of the residual SVG to RCA. On the other hand, the 31-year-old LITA graft revealed excellent patency (Panel and Supplementary material online, Video). Since the 1980s, the LITA for LAD grafting has been a cornerstone of CABG surgery.1 The European Society of Cardiology guideline recommends grafting with internal thoracic artery to the LAD as Class I.2 Furthermore, LITA graft had better patency than SVG for 20 years post-operatively.3 This case showed the over 30 years patency of LITA graft, although the use of a pump or the harvesting method might affect patency. This case indicated that it is precisely in patients less than 50 years of age scheduled for CABG that LITA to the LAD should be utilized.