The invention provides new derivatives of vitamin D, 24,24-difluoro-1.alpha.,25-dihydroxycholecalciferol and 24,24-difluoro-1.alpha.,25-dihydroxy-5,6-trans-cholecalciferol and processes for preparing the same.The compounds are characterized by vitamin D-like activity essentially equivalent to the vitamin D-like activity of 1.alpha.,25-dihydrocholecalciferol which is considered to be the hormonal form and most active derivative of vitamin D. The compounds of this invention are characterized by their ability to increase intestinal calcium transport, increase serum calcium and to prevent the development of rickets. These compounds would find ready application as a substitute for vitamin D and in the treatment of disease states evincing metabolic calcium and phosphorus deficiencies.