IMPORTANCE Treatment with aldosterone antagonists is recommended and has been shown to have beneficial effects in patients with ST-segment elevation myocardial infarction (STEMI) and left ventricular ejection fraction (LVEF) less than 40%. However, the role of aldosterone antagonists in patients with ejection fraction greater than 40% or without congestive heart failure is not well known. OBJECTIVES To perform a systematic review and meta-analysis using standard techniques to determine the role of therapy with aldosterone antagonists in this patient population. DATA SOURCES PubMed, Embase, CINAHL, and Cochrane Central databases were searched and a manual search for relevant references from the selected articles and published reviews was performed from database inception through June 2017. STUDY SELECTION Randomized clinical trials that evaluated treatment with aldosterone antagonists in patients with STEMI without clinical heart failure or LVEF greater than 40% were included. DATA EXTRACTION AND SYNTHESIS Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were used to conduct and report the meta-analysis, which used a random-effects model. Two investigators independently performed the database search and agreed on the final study selection. A manual search was performed for relevant references from the selected articles and published reviews. MAIN OUTCOMES AND MEASURES The outcomes analyzed were mortality, new congestive heart failure, recurrent myocardial infarction, ventricular arrhythmia, and changes in LVEF, serum potassium level, and creatinine level at follow-up. RESULTS In all, 10 randomized clinical trials with a total of 4147 unique patients were included in the meta-analysis. In patients who presented with STEMI without heart failure, treatment with aldosterone antagonists compared with control was associated with lower risk of mortality (2.4% vs 3.9%; odds ratio [OR], 0.62; 95% CI, 0.42-0.91; P = .01) and similar risks of myocardial infarction (1.6% vs 1.5%; OR, 1.03; 95% CI, 0.57-1.86; P = .91), new congestive heart failure (4.3% vs 5.4%; OR, 0.82; 95% CI, 0.56-1.20; P = .31), and ventricular arrhythmia (4.1% vs 5.1%; OR, 0.76; 95% CI, 0.45-1.31; P = .33). Similarly, treatment with aldosterone antagonists compared with control was associated with a small yet significant increase in LVEF (mean difference, 1.58%; 95% CI, 0.18%-2.97%; P = .03), a small increase in serum potassium level (mean difference, 0.07 mEq/L; 95% CI, 0.01-0.13 mEq/L; P = .02), and no change in serum creatinine level (standardized mean difference, 1.4; 95% CI, −0.43 to 3.24; P = .13). CONCLUSIONS AND RELEVANCE Treatment with aldosterone antagonists is associated with a mortality benefit in patients with STEMI with LVEF greater than 40% or without heart failure.