Previous reports have described an association between atrial septal aneurysm and cerebral embolic events. We report the case of 68-year-old woman who was referred for evaluation of two syncopal episodes that had occurred within the previous three months. Physical examination, 12-lead ECG and exercise stress test were unremarkable; a 24-hour Holter monitoring did not show cardiac arrhythmias, and carotid ultrasonography excluded atherosclerotic lesions. Magnetic resonance imaging of the brain revealed multiple areas of decreased tissue density. Two-dimensional transthoracic echocardiography showed an atrial septal aneurysm that was confirmed by transesophageal imaging, which improved its morphologic characterization and ruled out the possibility of other atrial abnormalities with embolic potential. In conclusion, the syncopal episodes observed in our patient were likely due to cerebral embolism. This observation confirms the relation between atrial septal aneurysm and cerebrovascular ischemic events. As previously indicated, the presence of this abnormality dictates the need for anticoagulant therapy.