This invention discloses 2-methylene-vitamin D analogs, and specifically (20S)-1α,25 -dihydroxy-2-methylene-vitamin D3 as well as (5E)-(20S)-1α,25-dihydroxy-2 -methylene-vitamin D3 and (20R)-1α,25-dihydroxy-2-methylene-vitamin D3, as well as pharmaceutical uses therefor. These compounds exhibit relatively high binding activity and pronounced activity in arresting the proliferation of undifferentiated cells and inducing their differentiation to the monocyte thus evidencing use as an anti-cancer agent especially for the treatment or prevention of osteosarcoma, leukemia, colon cancer, breast cancer, skin cancer or prostate cancer. These compounds also have relatively high calcemic activities evidencing use in the treatment of bone diseases.