Backgrounds: Depending on the lesion location, vessel size and type of lesions, bifurcation lesions may be associated with different early and mid-term outcomes. We sought to evaluate whether there are different early and mid-term clinical outcomes between in patients (pts) underwent PCI for left main (LM) and non LM bifurcation lesions. Methods: A total of 515 (male 69.7%, age 61.6짹10.6 years) pts who underwent percutaneous coronary intervention (PCI) for bifurcation lesions (LM; n=44 pts, or non-LM; n=471pts) between October 2003 and December 2007 were evaluated for major adverse cardiac event (MACE) in one month and six month period. Results: Baseline characteristics were similar between the two groups. Difference in MACE in one month after the PCI was not significant [3/44 (6.8%) vs 10/471 (2.1%); p=0.116, OR 3.317, CI 0.755-13.030]. At six months, pts with LM bifurcation group showed significantly higher MACE compared with the non LM bifurcation group [8/44 (18.2%) vs. 30/471(6.4%); p=0.013, OR 1.048, CI 1.010-1.088]. Multivariate analysis showed that the LM bifurcation lesion was an independent predictor of MACE at six month period (p= 0.007, OR 3.356 with CI 1.399-8.050). Conclusion: Although the LM bifurcation lesion was not associated with higher MACE in short term follow up compared with the non LM bifurcation lesion, with time, the incidence of MACE was significantly higher at 6-month. LM bifurcation lesion was a strong predictor for higher mid-term MACE.