Background: Chronic total occlusion (CTO) intervention is still challenging because of the limited procedural success rate and higher target failure. It is not clear whether diabetes mellitus (DM) will significantly impact on angiographic and clinical outcomes in CTO patients (pts) treated with drug eluting stents (DES). Methods: A total of 225 pts underwent CTO intervention with DESs were divided according to presence of DM (DM: n=74 pts, non-DM: n=151 pts). Six-month angiographic and twelve-month clinical outcomes were compared between the two groups. Results: The baseline clinical characteristics were balanced except more elderly pts (62.4짹8.6 vs. 59.2짹11.5, p=0.022) and hypertensives (74.6% vs. 60.3%, p=0.038) in the DM group. The overall procedural success rate was similar between the two groups (95.9% vs. 94.0%, p=0.543). Procedural characteristics and procedure related complications including perforation and dissection were not different between the two groups. At 6 months, the incidence of binary restenosis was higher in the DM group. However, the major clinical outcomes including death, Q-MI, repeat revascularization and major adverse cardiac events (MACEs) were similar between the two groups up to 12 months (Table). Conclusions: Despite the higher incidence of binary restenosis in DM group at 6 months, overall safety profile and major clinical outcomes were similar between the two groups, possibly due to high success rate of CTO intervention at index procedure. Long-term follow up with larger population will be necessary to elucidate final conclusion.