Bone metastases are a common feature of a variety of solid tumors and are associated with substantial skeletal morbidity, including severe bone pain and pathologic fractures. Treatment with bisphosphonates, primarily pamidronate, is the current standard of care for patients with breast cancer and multiple myeloma who have predominantly osteolytic lesions. However, until recently no bisphosphonate had demonstrated efficacy in patients with osteoblastic lesions, which are common during the progression of prostate cancer and other solid tumors. Zoledronic acid, a potent, new-generation, nitrogen-containing bisphosphonate, has demonstrated significant benefits for patients with bone metastases resulting from a broad range of primary tumors, including multiple myeloma and breast, lung, kidney, and prostate cancers, and other solid tumors. Benefits include a decreased incidence of pathologic fractures and longer time to the first skeletal complication. Zoledronic acid is the first and only bisphosphonate to be proved effective in patients with all types of bone lesions, from osteolytic to osteoblastic, and therefore represents an important therapeutic advancement in the treatment of bone metastases.