Background: The two main first generation drug-eluting stents (DES); Sirolimus- (SES; Cypher) and Paclitaxel (PES; Taxus) eluting stent is effective in reducing intimal hyperplasia but recently safety issues related to profound delayed healing and associated stent thrombosis was suggested. We compared the safety and efficacy of those two first generation DESs implanted in unprotected left main (LM) artery up to 12 months. Methods : All patients (pts) with unprotected LM lesion electively treated either with SES or PES was enrolled. LM bifurcation lesions were treated by kissing stenting, crushing technique or stent crossover (Stent/Balloon). All pts received aspirin, clopidogrel (300-600 mg) and/or cilostazol as the antiplatelet regimen and unfractionated heparin was given during the PCI. Clinical and angiographic outcomes up to 12 months were investigated.Results: Out of total 120pts who underwent standard percutaneous coronary intervention (PCI) on unprotected LM lesion, 68 pts (68/120, 56.7%) were exclusively treated with SES and 27 pts (27/120, 22.5%) with PES. At 6 months, although binary restenosis tend to be higher in the PES group but clinical outcomes showed no significant differences between the groups up to 12 months (Table). Conclusion: SES implantation was associated with a trend toward less angiographic binary restenosis compared with the PES. However, cumulative clinical outcomes were favorable and similar between the SESs and PESs up to 12 months.