Skeletal metastases occur commonly, and it is important to diagnose them early if the patient is to receive optimum treatment. The diagnosis of the lesion should include not only the site of the lesion and the degree and site of dissemination, but also the presence of any complications; the extent of soft tissue involvement, particularly with spinal metastases; and the vascularity of the lesion. The staging of the cancer may be important before starting treatment. Response to treatment should be assessed objectively, and as early as possible, so that if a patient has failed to respond, treatment can be altered. Many methods are available for the diagnosis of skeletal metastases and the assessment of their response to treatment. These methods are discussed in this article.