68 cases with 76 left ventriculographies, including rheumatic mitral valvular disease, congestive and hypertrophic types of cardiomyopathy, endocardial cushion defect, atrial and ventricular septal defects, coronary heart disease and mitral valve prolapse were analyzed with respect to the morphological and functional changes of the mitral valve and its appendages. Dynamic study with cineradiographic technic was the chief method used in this investigation. Except for ventricular septal defect, all the above-mentioned disease entities showed one or several of the changes of the mitral valvular apparatus including stenosis, insufficiency, displacement, cleft, deformity, prolapse and functional disorder. Regurgitation associated with mitral insufficiency exhibiting specific manifestations in different conditions was analyzed and its method of grading discussed. Mitral valve prolapse with its suggested method grading and functional disorder of the mitral valve were also discussed in detail.