The clinical files from the National Institute of Cardiology "Ignacio Chávez" were reviewed, we found 26 corroborated cases of ruptured aneurysms Valsalva's sinus. There is predominance of the male sex in proportion 3:1 and the median age when the diagnosis was made was 22 years. 77% of these cases were in N.Y.H.A. clinical class I or II and the main symptom was dyspnoea on exertion. On the physical examination a continuous murmur or sistolo-diastolic murmur was heard over precordium in 92% of the cases and a hyperkinetic circulatory regimen. Only in 23% of these patients the diagnosis was suspected and the more common confusion was with the V.S.D. associated with aortic incompetence. On the E.K.G. we found data with volumetric overload of the right heart in 15 cases. The hemodynamic study confirmed the diagnosis only in 60%. The aortic valve was substituted for associated incompetence in 12 cases and the pathological study revealed fibromixoid degeneration in 9 cases and only fibrosis in the remaining 3. The sinus of Valsalva more affected was the right coronary and the chamber where the rupture was more frequent was the right ventricle in 73% of the cases. We conclude that the ruptured aneurysms of the Valsalva's sinus is rather frequent among the congenital heart diseases and has particular clinical data and special features in making a precise diagnosis.