Congenital aneurysm or enlargement of the right atrium is a rare condition. Two children operated on at the age of 14 months and 11 years old for congenital aneurysm of the right atrium are reported. Both presented cardiomegaly and symptoms of paroxysmal supraventricular tachycardia. Diagnosis was established by echocardiography. Surgical resection was successful. Both patients are free of symptoms and their chest X-ray and echocardiogram are normal. The first patient is now in her 17th postoperative year. The patients' evolution suggests that the surgery is a curative procedure.