In two patients with a clinical picture of acute mitral insufficiency, the presence of chordal rupture secondary to myxomatous degeneration of the mitral valve was disclosed during surgery. There was no evidence of previous rheumatic valvulitis, subacute bacterial endocarditis or other etiologies. It appears from the literature and from the cases described that ruptured chorda tendinea is a not uncommon complication of myxomatous transformation of the mitral valve. While this fact has been mentioned in anatomophological reports, clinicians are less aware of the association. In the absence of supportive evidence for a rheumatic or arteriosclerotic etiology, a clinical picture of acute mitral insufficiency should suggest ruptured chorda tendinea secondary to myxomatous degeneration of the mitral apparatus. This is particularly true in older patients, especially among those followed for a midsystolic click-late systolic murmur or an apical pansystolic murmur of pure mitral regurgitation.