Atrial septal hematoma is uncommon complication that may happen after any cardiac intervention. Although it is rare, it can pose a challenging situation in the postoperative care. Multiple management approaches has been described with different outcomes. Here we are reporting a boy, aged 13 years, with dilated aortic root who underwent aortic root replacement with valve preservation. Postoperative course was complicated by atrial septal hematoma. A nonsurgical management approach was chosen based on the patient clinical condition. Regression in size with complete resolution of the hematoma was observed during the follow up. [ABSTRACT FROM AUTHOR]