Background: Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI). The CHA2DS2VASc and CHADS2 risk scores are used to identify patients with AF at risk for stroke and to guide oral anticoagulants (OAC) use, including patients with AMI. However, the epidemiology of AF, further stratified according to patients’ risk of stroke, has not been well characterized among those hospitalized for AMI. Methods: We examined trends in the frequency of AF, rates of discharge OAC use, and post-discharge outcomes among 6,627 residents of the Worcester, Massachusetts area who survived hospitalization for AMI at 11 medical centers between 1997 and 2011. Results: A total of 1,050 AMI patients had AF (16%) and the majority (91%) had a CHA2DS2VASc score >2. AF rates were highest among patients in the highest stroke risk group. In comparison to patients without AF, patients with AMI and AF in the highest stroke risk category had higher rates of post-discharge complications, including higher 30-day re-hospitalization [27 % vs. 17 %], 30-day post-discharge death [10 % vs. 5%], and 1-year post-discharge death [46 % vs. 18 %] (p<0.001 for all). Notably, fewer than half of guideline-eligible AF patients received an OAC prescription at discharge. Usage rates for other evidence-based therapies such as statins and beta-blockers, lagged in comparison to AMI patients free from AF. Conclusions: Our findings highlight the need to enhance stroke prevention among AMI survivors with AF.