Purpose Atrial arrhythmias (AA) are common post-lung transplant, with an incidence reported between 15-46%. The most frequently occurring atrial arrhythmia post-lung transplant is atrial fibrillation (AF). Current evidence suggests causation is likely multifactorial. Methods A retrospective cohort chart review of 194 lung transplants over a 4-year period at a specialist centre. Post-transplant arrhythmia was confirmed on continuous monitoring or 12-lead ECG. Univariate analysis was used to compare baseline characteristics, operative and post-operative factors as well as clinical outcomes. Results 64 patients had an arrhythmia post-transplant. The incidence of new AA was 28.86% (56/194), 2 had chronic AF and 6 developed a ventricular arrhythmia . Of the new AA, 75% (42/56) developed AF and 25% (14/56) developed other AAs (AFL/SVT). The mean time to new AA onset after transplant was 6.482 ± 4.027 (n=56) days. Of the 50 patients that developed AA in the ITU, 84% (42/50) received amiodarone to attempt cardioversion . Electric cardioversion was performed in 11/50 (22%) and rate control strategies were used in the other cases. Patients developing an arrhythmia were significantly older, more likely to be male and have a dilated left atrium . Within the arrhythmia group, 24-hour PaO2:FiO2 ratio was lower, the duration of ventilatory support was longer and the need for tracheostomy was higher (Table1). COPD patients undergoing lung transplant had the highest risk for AA 43.8% (25/57). 30-day survival in those who developed an arrhythmia was 89.1% (57/64), compared with 94.6% (123/130) in those who did not have an arrhythmia (Mantel-Cox logrank p=0.1622). Conclusion Arrhythmias post-lung transplant are common within the first week post-transplant. Our results support the findings of previous research including risk factors for arrhythmias and the necessity of prolong invasive ventilation . Further research is necessary to understand the significance of post lung transplant arrhythmias and identify preventative strategies.