The atrial septal aneurysm (ASA) is a morphologic abnormality known to cause peripheral and pulmonary embolism. 28-52% patients with ASA have embolic events. However ASA -- with no other concomittant cardiac patology has rarely been reported as the indication for open heart surgery. In this work, five cases of patients operated for ASA are presented. Embolic complications with cerebral symptoms were presented in three cases. The diagnosis of ASA was established with the use of transesophageal echocardiography. The surgical correction of the defect was performed in extracorporeal circulation. The aneurysmal part of interatrial septum was excised and replaced with a pericardial patch. The postoperative course was uneventful. The patients have no new embolic events during the follow up period of one year.