Background and aims: The presence of atrial fibrillation (AF) markedly increases the risk of stroke and mortality in patients. Whether AF is a risk factor for myocardial infarction (MI) is discrepant from current studies. The aim of this meta-analysis was to ascertain the association of AF with incident MI. Methods: Studies were identified through PubMed, CENTRAL, EMBASE, reviews and reference lists of relevant papers. Results of the MI outcome were presented as hazard ratio (HR) and 95% confidence interval (CI). Statistical analyses were performed with Stata 12.0 (Stata Corp LP, College Station, Texas, USA). Results: Twelve studies, with a total of 169,306 patients, were included in the analysis. AF was associated with a 47% increased risk of MI (HR: 1.47; 95% CI: 1.21-1.80; p = 0.000; I-2 = 84.1%), while in patients free of coronary heart disease at baseline the risk could be increased by 71% (HR: 1.71; 95% CI: 1.36-2.14; p = 0.000; I-2 = 83.1%). Moreover, patients with AF had higher MI risk in the studies with lower mean age (< 60 years) (HR: 1.66; 95% CI: 1.26-2.20; p = 0.000; I-2 = 82.9%) than in the studies with higher mean age (>= 60 years) (HR: 1.35; 95% CI: 1.00-1.82; p = 0.000; I-2 = 84.9%). Sex difference also existed, and the association between AF and MI was stronger in women (HR: 2.02; 95% CI: 1.60-2.56; p = 0.017; I-2 = 61.0%) than in men (HR: 1.44; 95% CI: 1.13-1.84; p = 0.000; I-2 = 76.1%). Conclusions: AF is associated with an increased risk of incident MI, especially in patients free of coronary heart disease at baseline, young patients and women. The findings need confirmation in well-designed observational trials. (C) 2016 Elsevier Ireland Ltd. All rights reserved.