The present invention provides methods of treating soft tissue calcificationin a subject, comprising a step of administering to said subject an effectiveamount of ferric organic compound, such as ferric citrate. The claimed methodsmay prevent , reverse, delay or stabilize soft tissue calcification in asubject having chronic kidney disease . Affected soft tissue calcificationincludes soft tissue calcification in the joint, skin, eye, in cardiovascularsystem such as heart valve, myocardium, coronary arteries and arteriole, or ininternal organs such as kidney and lung.