Background:Left main(LM) stent implantation is performed with different technique according to vessel size and plaque extent at its bifurcaton. We compared retrospectively the outcomes between 1 stent and 2 stent technique. Methods:The patients receiving LM intervention with drug eluding stent(DES) were searched in SNUBH data base. Pre, post- percutaneous coronary intervention(PCI), 6-month follow up quantitative coronary angiography data, inhospital and 6-month Major Adverse Cardiac Events(MACE), defined as cardiac death, myocardial infarction(MI) and target vessel revascularization(TVR), were analysed and compared between 1 and 2 stent technique. Contiguous or long stentings involving LM(> 33mm in stent length) were excluded. Results:From September, 2003 to December, 2006, 71 patients were treated with DES for their LM disease. Lesions were located in LM ostium(21.1%), shaft(9.9%), distal LM involving left anterior descending artery(LAD) or left circumflex artery(LCX) ostium(69%). 1 stent group were LM stenting alone or cross-over stenting(66.2%, n=47), 2 stent group were 21.1% kissing stenting, 9.9% Crushing stenting and 2.8% T or V stenting(n=24). There was no difference in baseline clinical characteristics. Both LAD and LCX ostium had more than 50% diameter stenosis(DS) in 75% of 2 stent group, in 26.1% of 1 stent group(p<0.001). 2 stent group had larger LM(3.61 vs 4.09mm, p=0.01),but 1 stent group received larger diameter stent in culprit vessel(3.35 vs 3.19mm in LAD, p=0.02). At post PCI, whereas minimal luminal diameter(MLD) and DS in LM to LAD were no difference, that in LM to LCX were higher in 2 stent group(1.94 vs 2.79mm,36.9% vs 17.8%, p < 0.01). However, late loss in LM to LCX was larger in 2 stent group(-0.03 vs 0.60mm, p=0.01). 6-month binary instent restenosis rate tended to be higher in 2 stent group(9.5% vs 24.4%, p=0.06). 6-month cardiac death and MI were no difference(2.1% vs 4.2%, p=0.56). 6-month TVR(8.5% vs 16.7%, p=0.25) and MACE(10.6% vs 20.8%, p=0.20) tended to be more frequent in 2 stent group. Conclusion:In spite of better post-PCI angiographic results, 2 stent technique showed the tendency of poorer angiographic and clinical follow-up results compared with 1 stent technique.