Ablation outcomes were investigated in patients with and without statin pretreatment before cardiac surgery with concomitant surgical ablation for atrial fibrillation (AF). A prospective cohort study was performed containing 149 patients (n=73 statin group vs. n=76 control group) undergoing on-pump cardiac procedures with surgical ablation for paroxysmal or persistent AF. Measured outcomes were freedom from AF in the intensive care unit, discharge and at three and six months follow-up and perioperative markers of inflammation (white blood cell count, C-reactive protein). Independent predictors for freedom from AF were assessed. Groups did not differ with respect to EuroSCORE, New York Heart Association class, left atrial size, anti-arrhythmic drug therapy or aortic cross-clamp time. Statin therapy had no impact on postoperative inflammatory markers. Freedom from AF was more frequent in the statin group at discharge (P=0.07) and after three and six months (P<0.05). Subgroup analysis showed that statin pretreatment was associated with higher rates of freedom from AF for paroxysmal AF at three and six months and for persistent AF after six months (P<0.05). Importantly, statin-pretreatment was independently predictive for freedom from AF at discharge [odds ratio (OR): 3.21; 95% confidence interval (CI): 1.2-8.55; P=0.02] and at three months (OR: 2.91; 95% CI: 1.14-7.45; P=0.026). Statin therapy prior to ablation surgery improves postoperative freedom from AF for paroxysmal and persistent AF in cardiac surgery patients.