BACKGROUND: Sudden cardiac death (SCD) is an important cause of death in patients with left-ventricular systolic dysfunction (LVSD). Mineralocorticoid receptor antagonists (MRAs) may attenuate this risk. We aimed to assess the impact of MRAs on SCD in patients with LVSD. METHODS: A fixed-effect meta-analysis at individual patient-level was performed using 11,032 patients recruited in three placebo-controlled randomized trials: Randomized Aldactone Evaluation Study (RALES), Eplerenone Post Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS), and Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF). Treatment effect was determined using a Cox proportional hazards model stratified by study. RESULTS: Patients receiving MRAs were at lower risk of SCD compared with placebo-treated patients after a mean follow-up of 18 months (HR 0.77, 95% CI 0.66-0.89). This effect was consistent across trials and did not change substantially after adjustment for 14 baseline co-variates. Moreover, the benefits of MRAs were consistent across study subgroups, except for a greater effect in those < 65 years old and those using beta-blockers. Using stratified analyses, we also found a consistent effect in relevant subsets of patient defined by heart failure cause, NYHA class or LVEF ≤ 35%. CONCLUSIONS: MRAs reduce the risk for SCD by 23% in patients with heart failure and LVSD. In these patients, the use of MRAs, on top of other evidence-based medications, should be optimized. It might be useful to re-assess the benefit of implantable cardiac defibrillator (ICD) placement, as ICD treatment effect was evaluated in trials enrolling patients not receiving MRAs.