Objectives: To assess long-term safety and efficacy of the Xposition S self-apposing stent in the treatment of unprotected left main coronary artery (ULMCA) disease. Background: Percutaneous intervention with stents has emerged as a valid alternative to surgical revascularization to treat ULMCA disease. Conventional balloon-expandable stents face technical challenges, particularly in large left main diameter requiring extensive optimization and side branch access in distal bifurcation. Xposition S allows for optimal apposition, bridging diameter differences, and allows expansion to vessel diameters up to 6.0 mm. Methods: Between June 2016 and July 2017, 205 patients were enrolled in this international, prospective, multicenter registry. Patients with SYNTAX score ≥ 33 or recent STEMI were excluded. IVUS during procedure was performed in a prespecified subgroup of 50 patients. The primary clinical endpoint was 12 months Target lesion failure (TLF) and the primary efficacy endpoint was angiographic success. Results: Distal left main bifurcation was involved in 92.7%, treated with provisional approach in most cases (79.4%). TLF rate at 12 months was 8.3%, which was defined as a composite of cardiac death (2.0%), target-vessel MI (2.9%), and TLR (5.4%). Most revascularizations occurred at SB ostium. IVUS analysis demonstrated optimal stent apposition with only one reported malapposition and promising poststenting minimal stent area measures. Conclusions: The TRUNC study confirms that Xposition S self-apposing stent is a valid and feasible option for the treatment of ULMCA disease. Such results were reached without the systematic need of stent optimisation techniques, focusing mainly on lesion treatment. 1 | INTRODUCTION Although coronary artery bypass grafting (CABG) is the historical gold standard, recent randomized studies suggest that percutaneous coronary intervention (PCI) is now a valid alternative for selected patients with unprotected left main coronary artery (ULMCA) disease. 1 In this complex population, the use of conventional balloon-expandable stents may present technical limitations, due to a fixed stent size, which