A 70-year-old woman, who had a history of a percutaneous transvenous mitral commissurotomy for rheumatic heart disease 34 years previously, was admitted with progressive right heart failure. Massive calcification of the left wall was observed on multidetector CT. She underwent a mitral valve replacement, tricuspid annuloplasty and permanent pacemaker implantation. Massive calcification of the left atrial wall is a rare condition, and constitutes a major complication and risk to mitral valve surgery because of the difficulty in entering the left atrium, potential embolization, and impaired hemostasis.