Background: Routine mid-term coronary angiographic follow up after bifurcation kissing stenting in unprotected left main (LM) angioplasty with drug-eluting stent (DES) rarely shows the organized neomembrane at the new metallic carina but its incidence and clinical significance has not been reported yet. We investigated the incidence and clinical significance at 6 to 8 month routine angiographic and clinical follow up. Method: All patients (pts) with unprotected LM were electively treated with sirolimus-eluting stent (SES; Cypher), paclitaxel-eluting stent (PES; Taxus) or zotarolimus-eluting stent (ZES; Endeavor). All pts received aspirin, clopidogrel (300-600 mg) and cilostazol as the triple antiplatelet regimen at least for a month and unfractionated heparin (UFH; 50 IU/Kg) was given during the PCI. Clinical and angiographic outcomes at 6 months were investigated. Results: Out of total 69 pts who underwent standard percutaneous coronary intervention (PCI) with DES on unprotected LM lesion, 26 pts who had LM bifurcation lesion were treated with kissing stenting. Kissing stenting for LM bifurcation lesions were treated by either simultaneous (n=19) or sequential (n=7) way. There were 3 pts neomembranes at the new carina at 6 month follow up (3/26 kissing stentings; 11.5%, 3/69 LM intervention; 4.3%). All 3 cases were observed after Cypher stent implantation. Selective intracoronary ultrasound examination showed newly organized intimal growth from the native coronary arterial wall toward the newly formed metallic carina after LM kissing stenting and was no significant plaque formation nor organized thrombus. All 3 cases were observed after simultaneous kissing stenting but was not significant (3/19 vs. 0/7 in sequential kissing, p=0.540). These 3 pts were clinically followed up to one year but there were no significant clinical cardiovascular events. Conclusion: The incidence of neomebrane after the LM kissing stenting in ���real-world clinical practice��� was 4.3% in all left main intervention and 11.5% in bifurcation kissing stenting. Despite the expected risk of this neomebrane at the new metallic carina, there were no worse outcome in terms of angiographic, IVUS and clinical follow-up up to one year.