Mitral regurgitation has become recognized as an important health problem. More specifically, functional mitral regurgitation is associated with worse outcomes in heart failure, postmyocardial infarction, and perioperative coronary artery bypass surgery patients. Many patients with severe mitral regurgitation are denied or refused mitral valve surgery. A less invasive procedure with possibly fewer potential complications may thus be attractive for patients with severe mitral regurgitation. Devices used for coronary sinus (CS) mitral annuloplasty are directed toward patients with functional mitral regurgitation. Because of its easy accessibility and close relationship to the posterior mitral annulus (MA), alterations of the CS geometry with percutaneous devices may translate to displacement of the posterior annulus and correct mitral leaflet coaptation. This review will focus on the contemporary CS annuloplasty devices: (1) Edwards MONARC system; (2) Cardiac Dimensions CARILLON; and (3) Viacor Shape Changing Rods system. In addition, important information obtained from recent imaging studies describing the relationship between the CS, MA, and coronary arteries will be reviewed.