Atrial septal aneurysm can be associated with other cardiovascular diseases such as atrial septal defect, patent ductus arteriosus, pulmonary hypertension and cerebrovascular events (transient ischemic attack or stroke). The introduction of transthoracic and more recently transesophageal echocardiography allowed for a more frequent observation of this pathology and also suggested that atrial septal aneurysm is a risk factor for cerebral ischemia. However, the pathophysiological pathway is still unclear. In January 1997 a 33-year-old man was admitted to our hospital because of atrial septal aneurysm and a previous cerebrovascular event. Magnetic resonance imaging revealed a cerebrovascular malformation and transesophageal echocardiography confirmed the presence of atrial septal aneurysm. We hypothesize that a common etiopathogenetic pathway may cause both the cardiac and cerebrovascular anomaly and that the latter may be responsible alone for cerebral ischemic events; thus in the presence of an atrial septal aneurysm associated with a cerebrovascular malformation, a conservative medical approach may be the treatment of choice.