Background Recent evidence supports the important role of inflammation in atrial fibrillation (AF) after coronary artery bypass grafting (CABG) and there is growing evidence that statin has cardiac antiarrhythmic effects. The aim of this study was to assess the efficacy of preoperative statins in preventing AF after CABG in a longitudinal observational study. Methods Over a two-year period, 405 consecutive patients underwent isolated CABG procedures. Univariate analysis was performed exploring the relationship regarding statin use and AF development. A propensity score for treatment with statins was obtained from core patient characteristics. The role of statin therapy on postoperative AF was assessed by means of a conditional logistic model, while stratifying on the quintiles of the propensity score. All analysis was performed retrospectively. Results Postoperative AF occurred in 29.5% of the patients with preoperative statin therapy compared with 40.9% of those patients without it ( p = 0.021). No statistical differences among development of AF and type, dose, or duration of preoperative statin therapy were observed. Preoperative statins were associated with a 42% reduction in risk of AF development after CABG surgery (odds ratio OR 0.58, 95% confidence interval CI 0.37 to 0.91, p = 0.017, while stratifying on the propensity score). No different effect of statins on AF was observed with respect to age groups (≤ 70 and >70 years) (interaction p = 0.711). Conclusions Preoperative statins may reduce postoperative AF after CABG. Patients undergoing elective revascularization may benefit from a preventive statin approach.