Postoperative atrial arrhythmia after thoracotomy is relatively common, with a reported incidence ranging from 8% to 30%. These arrhythmias may cause hypotension, congestive heart failure and lengthen the period of postoperative hospitalization. The most important precipitating factor is atrial dilation and identified risk factor is an advanced age of the patient. The effect of various prophylactic regimens to reduce atrial arrhythmias is controversial. We report a case of postoperative atrial fibrillation in a 73 year-old female patient undergoing repair of esophageal hiatal hernia.