In the era of drug-eluting stents (DESs), the angiographic rates of restenosis at later months have been dramatically reduced, but these rates have been less prominently reduced in diabetic patients. The rate of coronary restenosis is still higher in diabetic patients, when compared with non-diabetic patients, and even after DES implantation. Diabetes remains a significant predictor of coronary restenosis even in the era of DES, and especially in cases having a small baseline vessel size, a small post-PCI vessel size and a longer stent length. The use of the sirolimus-eluting stent in diabetic patients has been associated with a decreased rate of restenosis, and this suggests a reduced risk of target lesion revascularization. Diabetes still remains a major risk factor for coronary restenosis after DES implantation, and so aggressive risk factor management with the concomitant pharmacotherapy should be done to reduce the risk of coronary restenosis.