Background: Dual anti-platelet therapy (DAT) has been reported to prevent stent thrombosis after drug eluting stent (DES) implantation. However, the optimal DAT duration remains unclear. This study sought to investigate the duration of DAT after zotarolimus-eluting stents (ZES, Endeavor) implantation. Methods: A series of 329 consecutive patients were followed for at least 12 months after ZES implantation. We devided the patients into two groups, short-term DAT of 6 months as Group I (n=91, mean age 61.9 짹14.7 years, 68 male (74.7 %), and DAT more than 6 month as Group II (n=238, mean age 61.3 짹14.2 years, 150 male (63.0 %). Clinical outcomes after 8, 12 months and the incidence of late stent thrombosis (LST) were compared between groups. Results: Baseline clinical and procedural characteristics were similar between the two groups. After 8 month follow up, the MACE occurred in of 3 patients (3.2 %) with group I (3 TLRs) and 15 patients (6.3 %) with group II (2 MI and 13 TLRs)(p=0.222). After 12 month follow up, the MACE occurred in 3 patients (3.2 %) in group I (3 TLRs) and 9 patients (3.7 %) with group II (9 TLRs)(p=0.834). The LST was not occured in group I and occurred in 2 patients (0.8%) in group II (p=0.382) Conclusion: Short term DAT of six-month was safe and effective to prevent MACE and LST after ZES implantation in real world setting. Further large scale, prospective study about the duration of DAT after DES should be needed.