Background and Objectives Serum troponins are sensitive markers of cardiac myonecrosis and ischemia. Troponin elevation after percutaneous coronary intervention (PCI) is considered to represent the irreversible myocardial injury and associated with worse clinical outcomes. Drug-eluting stent (DES) can be implanted in multiple, long lesions which is not possible in the bare metal stent era. We investigated the incidence, risk factors and clinical outcomes of elevated troponin-I (TnI) levels after implantation of DES. Methods and Results We performed a retrospective analysis on 518 coronary stenting cases over an 18-month period at a single center. All patients who received drug-eluting stents were analyzed. Patients who have acute coronary syndrome with elevated TnI levels before PCI were excluded. Finally 335 patients were analyzed. TnI levels were measured 4-6 h after PCI and the next morning. Baseline clinical characteristics were similar between the elevated and the normal TnI groups. An elevated post-procedural TnI (>1.5 ng/ml) occurred in 52 patient (15.5%). A univariate analysis revealed that clinically significant variables were total stent length (P=0.001), stent number (P=0.014), and side-branch occlusion (P=0.025). Levels of TnI correlated increasingly with stent length (P<0.01). After multivariate analysis, independent predictor of elevated TnI after implantation of DES was total stent length. There were no significant differences in major adverse cardiovascular events between elevated and normal TnI groups (P=0.508). Conclusion Stent length, stent number and side-branch occlusion are significantly associated with TnI elevation after implantation of DES. Stent length is an independent predictor of elevated TnI after implantation of DES.