We describe a rare association between congenital muscular ventricular septal aneurysm (MuVSA) and right heart lesions, with emphasis on echocardiographic diagnosis, clinical presentation, and outcome. Our four cases of MuVSA occurred in combination with either pulmonary atresia with intact ventricular septum (PAIVS; three patients) or absent pulmonary valve syndrome with severe tricuspid stenosis (one patient). MuVSA and right heart lesions were detected in utero in three patients. The three patients with PAIVS and MuVSA survived with no significant morbidity from the septal aneurysm at 3- to 5-year follow-up. The presence of MuVSA did not negatively affect the outcome of our patients.