Background:Diabetes mellitus(DM) has been known to be one of the adverse prognostic factors after the PCI even in DES era. There are limited data regarding PCI with DES on diffuse lesion(>30mm) in pts.Methods:From Sept 2004 to Dec 2006,total 853 pts underwent PCI with DES and a total 267 pts with diffuse coronary lesions with DES (Cypher짰, Taxus짰 or Endeavor짰).Angiographic and clinical outcomes of DM group(n=108) were compared with those of non DM group(n=159) at 6 months.Results:Baseline characteristics were not different in both groups except serum creatinine(1.30짹1.3 vs 1.00짹0.3, p=0.02) was higher and LDL level is lower(104.4짹36.1 vs 115.6짹40.1, p=0.04) in the DM group.The reference vessel diameter (pre RVD) was smaller in DM group(2.94짹0.47 vs 3.08짹0.55,p=0.03), but there was no difference in lesion length (45.5짹18.2mm vs. 46.4짹22.0mm, p=NS).At 6 months, although follow up MLD was lower and late loss was higher in DM group, binary restenosis was not different between the two groups.Focal ISR was more frequent in DM group.However, mid-term clinical outcomes were not different between two groups(Table).Conclusions:In DM pts with diffuse coronary lesion, although they had we smaller vessel size, angiographic binary restenosis are clinical outcomes were not different compared to those of non DM group. These results might be originated from salutary effects of DES on diffuse coronary lesion in DM pts.