Atrial septal aneurysm (ASA) is a well-recognized cardiac abnormality of uncertain clinical significance. It has early been reported as an unexpected finding during autopsy, but it may also be diagnosed in living patients by echocardiographic techniques. An association between ASA and focal cerebral ischemic events has been suggested. Nevertheless, the role of ASA as a risk factor for cerebral ischemia is poorly defined. Several studies have demonstrated a significantly higher proportion of ASA in the patients referred for transesophageal echocardiography after a cerebral ischemic event of unknown cause. However, ASA is often associated with other cardiac abnormalities such as patent foramen ovale, atrial septal defects, as well as mitral valve prolapse or atrial arrhythmias. Due to the fact that these abnormalities are also possible sources of cardiac emboli it is even more difficult to assess the embolic potential of an ASA, independently. In this review, we have examined most of the papers on this topic to try to define the prevalence of ASA in the stroke patients and how this abnormality could be a risk factor for recurrences of cerebrovascular events.