Real time 3-D echocardiography (RT3DE) images allow noninvasive evaluation of the three dimensional geometry of the mitral annulus [1]. In this study, we propose a computer aided method for the assessment of the geometry of the mitral annulus and the analysis of the motion of the mitral annulus throughout the cardiac cycle from RT3DE. The method consists of the following four steps. (A) marking the boundary points on the mitral annulus, (B) re-arranging these marked points into a set of series of points on a closed contour, i.e. the saddle-shaped mitral annulus, (C) describing the mitral annulus by a spline model, (D) computing three new dynamic parameters.