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Background: Atrial fibrillation (AF) is the most common coronary artery bypass graft (CABG) post-operative arrhythmia. This complication can increase the patient’s chances for a more extended hospital stay, stroke, or death; resulting in additional healthcare costs. Prescribing statins (3-hydroxy-3-methylglutaryl COA reductase inhibitors) to reduce the risk of postoperative AF (POAF) is well studied, as they provide an anti-inflammatory and antioxidant benefit within hours of initiation. However, whether the statin type or dose is the origin for these benefits remains unknown; as research is conflicted. Methods: This ten-year retrospective observational study at a single institution, included all patients who underwent an isolated CABG; between January 1, 2005 - December 31, 2015 (n=3,226). For multiple CABG procedure cases, only the first incidence was included. Cases with a pacemaker, history of AF before CABG, or inflammatory disease that requires chronic steroid therapy, were excluded. The final population totaled 1,842 (non-AF n=867; AF n=975) cases, respectively. We analyzed the data using two-sample t-tests and chi-square tests to identify which patient characteristics were significantly associated with having POAF. To keep a representative sample of our study population, variables missing more than 80% of values were excluded. Multiple logistic regression was used to identify which combination of characteristics were most significant and then statin dose and type were each added to the model, individually and together. These two variables were highly correlated, thus for our final model, we used a professional statin dose comparison resource guide to create a dose-intensity variable that considered the type of statin and dose. Patients prescribed no statin was classified as a no dose group, while those prescribed statins were classified into a low, medium or high-intensity dose group. Results: The characteristics associated with a risk of POAF were age, history of vascular disease, and cardiomegaly. While, history of carotid disease, IV heparin within 24 hours of pre-op, and aspirin use were associated with a lower risk of POAF. Patients receiving a high-intensity dose had the lowest rate of POAF (46% vs. 67% for no statin, 57% for low and 53% for moderate, p Conclusion: According to this CABG population analysis, a history of carotid disease, IV heparin within 4 hours of pre-op, and aspirin use were associated with a lower risk of POAF and both statin dose and type are essential factors in POAF prevention. High-intensity dose statins had the lowest rate of POAF, and a one day shorter hospital stay whereas simvastatin had the lowest and atorvastatin had the highest incidence of POAF.