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, however, the its incidence and impact on long-term clinical outcomes are not clarified yet.Method: All patients (pts) with unprotected LM were electively treated with Drug eluting stents (DES) and investigated for incidence and clinical significance at 6 to 8 month routine angiographic and clinical follow-up up to 5 years. Results: Out of total 118 pts who underwent standard PCI with DES on unprotected LM lesion, 28 pts with LM bifurcation lesion were treated with kissing stenting (19 Simulateneous Kissing and 9 Sequential Kissing Stenting). There were 6 pts were found to have neomembranes at the new metallic carina in the LM kissing stenting site at 6 to 8 months follow up. All of the 6 pts were treated with Cypher stents. Overall incidence of neomembrane among the LM intervention cases was in 5.1% (6/118) and among the bifurcation kissing stenting cases was in 21.4% (6/28). 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 no significant plaque formation or organized thrombus. Five cases were observed after simultaneous kissing stenting, whereas only 1 case was observed after sequential kissing stenting (5/19, 26.3% vs. 1/9, 11.1%, p=0.63). There were no significant clinical cardiovascular events up to 5 years. Conclusion: The incidence of neomembrane after LM kissing stenting was approx 20% and all were developed after Cypher stenting, especially after the simultaneous kissing stenting. Despite the expected risk of this neomembrane at the new metallic carina, there were no adverse cardiac outcomes up to 5-year following LM kissing stenting, either simultaneous or sequential strategy.