Background: Whether final kissing balloon (FKB) dilatation after one-stent implantation at left-main (LM) bifurcation site remains unclear.Therefore, this large sample and long-term follow-up study comparatively assessed the impact of FKB in patients with unprotected LM disease treated with one-stent strategy.Methods: Total 1528 consecutive patients underwent LM percutaneous coronary intervention in one center from January 2004 to December 2010 were enrolled;among them, 790 patients treated with one drug-eluting stent crossover LM to left anterior descending (LAD) with FKB (n =230) or no FKB (n =560) were comparatively analyzed.Primary outcome was the rate of major adverse cardiovascular events,defined as a composite of death, myocardial infarction (MI) and target vessel revascularization (TVR).Results: Overall, The prevalence of true bifurcation lesions, which included Medina classification (1,1,1), (1,0,1), or (0,1,1), was similar between-groups (non-FKB: 37.0% vs.FKB: 39.6%, P =0.49).At mean 4 years follow-up, rates of major adverse cardiovascular events (non-FKB: 10.0% vs.FKB: 7.8%, P =0.33), death, MI and TVR were not significantly different between-groups.In multivariate propensity-matched regression analysis, FKB was not an independent predictor of adverse outcomes.Conclusions: For patients treated with one-stent crossover LM to LAD, clinical outcomes appear similar between FKB and non-FKB strategy.