Background: There is little data on predictive factors of peri-procedural myocardial infarction (PPMI) after intracoronary stent implantation for bifurcation lesion. Methods and Results: We analyzed 1,210 patients enrolled in Coronary Bifurcation Stenting (COBIS) registry which was retrospective registry of drug-eluting stenting for bifurcation lesions in 16 centers of Korea. Of them, 243 patients (20.1%) suffered from PPMI were assigned to group I and 967 patients free from PPMI to group II. PPMI was defined as 3-fold increase in cardiac enzymes after procedure, and patients initially diagnosed with MI were excluded. We compared one-year major adverse cardiac events (MACE) defined as cardiac death, MI, any revascularization between two groups. There was no difference in the stenting technique between two groups. During one-year follow-up, no difference was observed in the incidence of cardiac death and target lesion revascularization (TLR) between two groups. However, group I had higher incidence of MACE than those of group II (16.9% vs. 12.1%, p=0.048 respectively). In multivariate analysis, acute closure in side branch (SB), ejection fraction, true bifurcation, and unstable angina were independent predictors for PPMI (HR=3.509; 95% CI=1.722-7.150, HR=0.983; 95% CI=0.968-0.998; HR=1.690; 95% CI=1.018-2.807, HR=3.101; 95% CI=1.031-9.327 respectively). In Cox regression analysis, sirolimus-eluting stent implantation in parent vessel and SB calcification were independent predictors for MACE (HR=0.592; 95% CI=0.426-0.823, HR=1.720; 95% CI=1.088-2.719). Conclusions: This study demonstrated that PPMI was independently associated with acute closure in SB, lower ejection fraction, true bifurcation lesion and diagnosed as unstable angina in patients with intracoronary stent implantation for bifurcation lesion.