An echocardiogram is the graphic registration of ultrasound waves reflected from the heart. The waveform recording from the anterior leaflet of the mitral valve is specific for this structure. The mitral valve echocardiogram in patients with solitary mitral stenosis correlates well with the findings obtained through cardiac catheterization and with observations made during open-heart surgery. The motion of the anterior leaflet expressed as a diastolic slope in millimeters per second has been shown to decrease as the mitral valve area lessens. The echocardiogram, obtained without risk or serious technical difficulty, can be used in determining the severity of mitral stenosis. This bedside procedure may also be used to study the evolution of mitral stenosis from the onset of rheumatic activity and to appraise the motion of the leaflet after mitral valvotomy.