Anterolateral thoracotomy is frequently used for the closure of ostium secundum atrial septal defect (ASD). The cosmetic result has become an important feature. There are various complications of anterolateral thoracotomy like persistent postoperative pain, phrenic nerve injury, atelectasis, and bleeding. We report a case of ASD closure through anterolateral thoracotomy who had bleeding of the left atrial appendage (LAA), which is an unusual and rare complication.