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 the angiographic and clinical outcomes in patients (pts) with CTO treated with drug eluting stents (DES).Methods A total of 184 pts underwent CTO intervention with DESs were compared according to presence of diabetes mellitus (DM: n=65 pts, non-DM: n=119 pts). In-hospital and 6-month outcomes were compared between the 2 groups.Results The baseline clinical characteristics were balanced except more male (58.5% vs. 79.0%, p<0.01) in non-DM group and the DM group were older (62.2짹8.5 vs. 58.3짹11.9, p=0.01) and more hypertensive (76.9% vs. 50.4%, p<0.01). The overall procedural success rate is similar between the two groups (96.9% vs. 93.2%, p=0.33). Procedural characteristics and procedure related complications including perforation and dissection were not different between two groups. At 6 months, these 2 groups had similar had favorable clinical and angiographic outcomes including the rate of binary restenosis, late loss, death, Q-MI, TVR and MACE (Table). Conclusions The safety profile and mid-term angiographic and 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.