Cancers of the breast and prostate are very common in the general population, with breast cancer accounting worldwide for 23% of cancer cases in women and prostate cancer accounting for 12% of cases in men. During the past decade, the survival rates of patients with estrogen-dependent breast cancer and testosterone-dependent prostate cancer have improved. This improvement has been possible thanks to the introduction of hormone treatments that suppress the synthesis or antagonize the actions of gonadal steroids. However, estrogen and testosterone deficiencies are associated with excessive bone resorption that translates into damage of the bone microarchitecture, loss of bone mineral density, and predisposition to osteoporosis and fractures. Herein, we review the mechanisms of bone loss in breast and prostate cancer survivors, their clinical implications, and different available therapeutic modalities that may help to correct the damage of bone and prevent the development of fractures.