Background: Atrial arrhythmias (AAs) are frequent after lung transplantation (LT) and late postoperatively. Several predictive factors of early postoperative AAs after LT have been identified but those of late AAs remain unknown. Whether AA after LT affects mortality is still being debated. This study assessed in a large cohort of LT patients the incidence of AAs early and late after surgery, their predictive factors and their effect on mortality. Methods and Results: We studied 271 consecutive LT patients over 9 years. Mean follow-up was 2.9 2.4 years. 33% patients developed postoperative AAs. Age (odds ratio (OR) 2.35; confidence interval (CI) [1.31-4.24]; P=0.004) and chronic obstructive pulmonary disease (OR 2.13; Cl [1.12-4.03]; P=0.02) were independent predictive factors of early AAs. Late AAs occurred 2.2 2.7 years after transplant in 8.8% of the patients. Pretransplant systolic pulmonary arterial pressure (PTsPAP) was the only independent predictive factor of late AA (OR 1.028; CI [1.001-1.056]; P=0.04). Double LT was associated with long-term freedom from atrial fibrillation (AF) but not from atrial flutter (AFL). Early and late Ms after surgery had no effect on mortality. Double LT was associated with better survival. Conclusions: Early AA following LT is common in contrast with the low occurrence of late, often organized, AA. Early and late AAs do not affect mortality. PTsPAP is an independent predictor of late AA. Double LT protects against late AF but not AFL.