AIMS: Percutaneous coronary intervention (PCI) is increasingly being used for unprotected left main (ULM) disease. Limited data are available on sex-related differences in this setting. We investigated gender-associated differences in patients undergoing stent-based PCI for ULM. METHODS AND RESULTS: We analysed baseline, procedural and long-term data of patients with ULM undergoing stent-based PCI at participating centres. The primary end-point was the long-term rate of major cardiovascular events rate (MACE, i.e., the composite of death, myocardial infarction, or target lesion revascularisation). The study population included 1,452 cases, with 27.8% females and 72.2% males. Women were older, more frequently diabetic, hypertensive or presenting with an acute coronary syndrome, and thus with a higher EuroSCORE, but were less commonly treated with drug-eluting stents (DES), in comparison to men (all p