Empagliflozin improves cardiovascular outcomes in patients with heart failure, patients with type 2 diabetes who are at high cardiovascular risk, and patients with chronic kidney disease. The safety and efficacy of empagliflozin in patients who have had acute myocardial infarction are unknown.In this event-driven, double-blind, randomized, placebo-controlled trial, we assigned, in a 1:1 ratio, patients who had been hospitalized for acute myocardial infarction and were at risk for heart failure to receive empagliflozin at a dose of 10 mg daily or placebo in addition to standard care within 14 days after admission. The primary end point was a composite of hospitalization for heart failure or death from any cause as assessed in a time-to-first-event analysis.A total of 3260 patients were assigned to receive empagliflozin and 3262 to receive placebo. During a median follow-up of 17.9 months, a first hospitalization for heart failure or death from any cause occurred in 267 patients (8.2%) in the empagliflozin group and in 298 patients (9.1%) in the placebo group, with incidence rates of 5.9 and 6.6 events, respectively, per 100 patient-years (hazard ratio, 0.90; 95% confidence interval [CI], 0.76 to 1.06; P = 0.21). With respect to the individual components of the primary end point, a first hospitalization for heart failure occurred in 118 patients (3.6%) in the empagliflozin group and in 153 patients (4.7%) in the placebo group (hazard ratio, 0.77; 95% CI, 0.60 to 0.98), and death from any cause occurred in 169 (5.2%) and 178 (5.5%), respectively (hazard ratio, 0.96; 95% CI, 0.78 to 1.19). Adverse events were consistent with the known safety profile of empagliflozin and were similar in the two trial groups.Among patients at increased risk for heart failure after acute myocardial infarction, treatment with empagliflozin did not lead to a significantly lower risk of a first hospitalization for heart failure or death from any cause than placebo. (Funded by Boehringer Ingelheim and Eli Lilly; EMPACT-MI ClinicalTrials.gov number, NCT04509674.).