A 54-year-old woman with pseudoxanthoma elasticum presented with tight mitral stenosis with thickened and restricted mitral valve leaflets. She initially revealed systemic hypertension and moderate mitral regurgitation due to mitral valve prolapse. One year after the start of treatment for hypertension, thickening of the mitral valve gradually progressed and she showed tight mitral stenosis without regurgitation. It was considered that another differential diagnosis must be added to the uncommon causes of mitral stenosis.