Sinus of Valsalva aneurysm (SVA) arises frequently in the right coronary sinus, and ventricular septal defect (VSD) is a prevalent coexistent cardiac abnormality. A 38-year-old asymptomatic male diagnosed with VSD on cardiac catheterization in his childhood, was referred to our hospital for the change in intensity of his cardiac murmur pointed out by his family physician. A grade V continuous murmur was auscultated with a thrill loudest at the forth left sternal border. Although, transthoracic and transesophageal echocardiography and cardiac catheterization have showed the ruptured right coronary sinus aneurysm, it was difficult to demonstrate coexistence of a doubly committed subarterial VSD. Three-dimensional echocardiography could provide clear images for diagnosis of the VSD closely adjacent to the ruptured SVA. The defect was confirmed at surgery.