Background: Atrial fibrillation (AF) is common after open-chest procedures, but the etiology remains poorly understood. Lung transplant procedures allow for the study of novel contributing factors. Methods: Records of lung transplant procedures performed at a single center between 2002 and 2009 were reviewed. Results: Of 174 patients, 27 (16%) had AF a median 6 days post-surgery. Post-operative AF patients less often had right ventricular hypertrophy (RVH) by either electrocardiogram (0 versus 14%, P =.042) or echocardiography (19% versus 47%, P =.006), and had lower pulmonary artery systolic pressures (PASP) (39 ± 12 versus 51 ± 22, P =.005). After multivariable adjustment, every 10-mm Hg increase in PASP was associated with a 31% reduction in the odds of post-operative AF (OR 0.69, 95% CI 0.49-0.98, P =.035). A higher pulmonary pressure was the only predictor independently associated with less post-operative AF. Conclusions: Higher PASP was associated with a lower risk of AF after lung transplantation. © 2013 Elsevier Inc. All rights reserved.