Valve repair is the best operation currently available for patients with mitral valve disease. However, repair is technically more difficult than valve replacement and has a risk of early and late failure. Echocardiography permits better diagnosis and management of these problems. Preoperative echocardiography, including Doppler color flow mapping to evaluate intracardiac flow, is used to assess the feasibility of repair. Intraoperatively, epicardial and transesophageal echocardiography are used to monitor surgical results immediately after repair, ensuring successful outcome of surgery.