The present invention provides novel C24-sulfone analogs of 1.alpha.,25-dihydroxy vitamin D.sub.3, compositions comprising these compounds and methods of using these compounds as selective inhibitors of CYP24. In particular, the compounds of the invention are useful for treating diseases which benefit from a modulation of the levels of 1.alpha.,25-dihydroxy vitamin D.sub.3, for example, cell-proliferative disorders.