Ruptured aneurysms of the sinus of Valsalva are relatively rare, and the incidence seems to be higher in oriental than in western countries. Valsalva sinus aneurysm consists of a separation or lack of fusion behveen the media of the aorta and the annus fibrosis of the aortic valve. Rupture usually occurs in the third or fourth decade of life, most often between the right coronary cusp and the right ventricle, but occasionally, when the noncoronary cusp is involved, the fistular drains into the right atrium. Abrupt rupture causes chest pain, bounding pulses, a continuous murmur, and volume overload of the heart. Associated cardiac lesions are common including VSD and AR. We experienced a typical case of ruptured aneurysm of the sinus of Valsalva into RA in a 31 year-old man presented sith sudden dyspnea, chest pain and palpitation. Diagnosis was made by 2D-echocardiography, cardiac catheterization and cine-angiogram. This case, the aneurysm was originated from the noncoronary sinus and ruptured into right atriurn. The ruptured aneurysm were repaired mth Dacron patch.