Described are new agents for treating bone disorders associated with a reduction in bone mass and abnormalities in bone resportion or bone formation including osteoporosis. Paget's disease, bone metastases and malignant hypercalcemia. The agents are hydroxyl containing steroidal hormones, having bone resportion antagonist or bone formation stimulatory activity, covalently linked through the hydroxyl group via a bond hydrolyzable in the human body, e.g. carbamate or carbonate, which is further covalently linked to an amino, or hydroxy substituted alkylidene-1,1-bisphosphonate, through the respective amino or hydroxy group. The alkyl bisphosphonate moiety confers bone affinity. The agent acts by delivering the steroidal hormone directly to the bone target site where it is released for bone resorption antagonist or bone formation stimulatory action by hydrolysis of the hydrolyzable covalent bond.