To date, the assessment of rheumatic mitral stenosis has been based on Doppler methods, which have a high dependence on the hemodinamic conditions and on the planimetry obtained from 2D echo images. Real Time 3D echocardiography has been implemented in the daily clinical practice. It provides high quality 3D images and the acquisition time is very short. In the present work, we try to show the "state of the art" of Real Time 3D echocardiography in the assessment of rheumatic mitral stenosis. These findings are based on the experience of our "Unidad de Imagen Cardiovascular" at the Hospital Clinico San Carlos de Madrid.