A 70-years-old woman who had been on hemodialysis for 8 years was referred to our institution to undergo mitral surgery for mitral valve stenosis. Intraoperative investigations confirmed severe calcification of the posterior mitral leaflet and all-around mitral annulus. We excised the mitral leaflet using the Ultrasonic Surgical System and preserved the calcified annulus to prevent a fatal complication such as left ventricular rupture. We passed 2-0 polyester mattress sutures through the calcified annulus from the left ventricle to the left atrium, and mitral valve replacement was performed using a reversed 19 mm On-X mechanical heart valve for the aortic valve. The postoperative course was uneventful. Mitral annular calcification is a factor of fatal complications such as left ventricle rupture and coronary artery injury. We succeeded in preserving the calcified annulus and using a small diameter mechanical heart valve.