Immunosuppressant agents are used widely for a variety of diseases, and their usage will increase as organ transplantation becomes more frequent. One of the consequences of their administration is the occurrence of rapid bone loss with fractures. Generally, glucocorticoids (GC) are the main culprit, but calmodulin-calcineurin phosphatase inhibitors, e.g., cyclosporine and tacrolimus, seem to play a role as does the underlying disease, which necessitates treatment or organ transplantation. The mechanisms for the bone disease are multifactorial and actively being researched. The management at present is largely empirical and consists of calcium, vitamin D, and antiresorbers, especially bisphosphonates. In order to achieve an optimum treatment strategy, bone density measurements are essential to define the severity of the bone loss, help decide therapy and monitor progress of the patient.