Fifteen cases of severe mitral regurgitation secondary to ruptured chordae tendineae have been reviewed, eight of whom underwent open-heart surgery to correct their lesions. Three patients are living at this time with two being markedly improved. Cardiac catheterization was performed in six prior to surgery.Progressive deterioration within the year following the onset of difficulty or sudden worsening of previous cardiac symptoms characterized the usual clinical course. The apical systolic murmur, always loud, was conspicuously harsh and radiated to the base of the heart, simulating aortic stenosis when the mural cusp was ruptured. Although strongly suggesting the diagnosis, the sudden onset of an apical systolic murmur could be documented in only three instances. The presence of a small left atrium radiographically with tall left atrial “v” waves and marked reflux of contrast material into a paradoxically pulsating left atrium also pointed to the correct diagnosis.Various technics of surgical repair and problems influencing survival of patients in the present series are discussed.