The spontaneous closure of ventricular septal defects is frequently associated with septal aneurysm formation. In this paper we discuss the M-mode two-dimensional echocardiographic findings in nine children with aneurysms of the ventricular septum in association with ventricular septal defects. In all patients the diagnosis was confirmed by angiography. The ventricular septal aneurysms were detected by both M-mode two-dimensional echocardiography. With M-mode echocardiography, septal aneurysms could be recognized by a pattern of multiple systolic echoes within the right ventricle. With two-dimensional echocardiography, the protrusion of the septal aneurysm into the right ventricle could be seen from several views the location the relative size of the aneurysm assessed. Echocardiographic techniques useful in the detection of ventricular septal aneurysms are discussed examples presenteD.