The familial origin of atrial septal defects has been previously reported. This is the first study describing 2 families with atrial septal aneurysm of familial origin. The present study represents both clinically manifested and silent atrial septal aneurysms. Moreover, female gender predominance is also reported. Based on the presented data it could be suggested that all first-degree relatives of affected patients should be screened by cross-sectional echocardiography, particularly if they are women. In these patients, the use of aspirin might be the first line of treatment.