Aims: We performed a meta-analysis of randomised trials comparing percutaneous coronary intervention (PCI) with stent implantation to coronary artery bypass grafting (CABG) for the treatment of unprotected left main coronary artery stenosis (ULMCA). Methods and results: Pubmed and other databases were searched. Data were expressed as odds ratios (OR) with 95% confidence interval (CI). Four randomised trials enrolling 1,611 patients were selected. At 12-month follow-up PCI, as compared to CABG, was associated with a significant risk reduction of stroke (0.12% vs. 1.90%, OR 0.14, 95% CI [0.04 to 0.55], p=0.004), with an increased risk of repeat revascularisation (11.03% vs. 5.45%, OR 2.17, 95% CI [1.48 to 3.17], p <0.001), a similar risk of mortality (OR 0.72,95% CI [0.42 to 1.24], p=0.23) or myocardial infarction (OR 0.97, 95% CI [0.54 to 1.74], p=0.91), leading to an increased risk of major adverse cardiovascular events (14.37% vs. 10.14%, OR 1.50, 95% CI [1.10 to 2.04], p=0.01) and similar hazard of major adverse cardiac or cerebrovascular events (14.49% vs. 12.04%, OR 1.24, 95% CI [0.93 to 1.67], p=0.15). Conclusions: PCI is comparable to CABG for the treatment of ULMCA with respect to the composite of major adverse cardiovascular or cerebrovascular events at 12-month follow-up.