Background: Unprotected left main (LM) angioplasty with drug-eluting stent (DES) in patients (pts) with preserved left ventricular (LV) function has been challenged in some selective centers but ���real-world clinical practice��� regardless of LV dysfunction has been controversial. We evaluated the safety and efficacy of DES implantation in LM or its bifurcation lesion regardless of LV dysfunction up to 6 months in a single center registry. Methods: All patients (pts) with unprotected LM regardless of LV dysfunction were electively treated with either sirolimus-eluting stent (SES; Cypher) or paclitaxel-eluting stent (PES; Taxus). All pts received aspirin, clopidogrel (300-600 mg) and/or cilostazol as the antiplatelet regimen and unfractionated heparin (UFH; 50 IU/Kg) was given during the PCI. Early and mid-term clinical and angiographic outcomes were investigated. Results: A total 54 pts (Male 31, mean age, 62.5 짹 9.9 years) who underwent standard percutaneous coronary intervention (PCI) with DES on unprotected LM lesion were enrolled. Eleven pts (11/54, 20.4%, mean EF=34%) had LV dysfunction (moderate in 7 pts, mean EF=28%, mild in 3 pts, mean EF=44%). Target lesions were 31 LM bifurcations, 13 LM ostial, 10 LM body to LAD lesions. Seventy percent (22/31) of bifurcation lesions were treated by kissing stenting technique (18 Simultaneous, 4 Sequential). All pts were treated by PES in 25.9% (14/54) and by SES in 74.1% (15/54). Mean DES diameter was 3.06 mm and length was 22.4 mm in bifurcation lesions. Only one pt with acute myocardial infarction (MI, EF 50%) had acute stent thrombosis in non-target lesion. At 6 months, 6 pts (6/54, 11.1%) showed asymptomatic angiographic binary restenosis, focal type but there was no additional revascularization. There were 3 deaths (1-cardiac, 2-non-cardiac, 3/54, 5.6%) up to 6 months. Conclusion: Despite the expected higher risk of LM disease, DES implantation in unprotected LM regardless of LV dysfunction appears safe and associated with low angiographic restenosis and favorable clinical outcomes up to 6 months.