Bone is the most common site for metastasis from solid tumors, and the majority of patients will develop bone metastases during the natural course of their disease. Bisphosphonates are an effective treatment for preventing skeletal-related events in patients with bone metastases and may preserve functional independence and quality of life. Although several bisphosphonates have been investigated in patients with solid tumors, only zoledronic acid (ZOL) is approved by the US Food and Drug Administration and the European Medicines Agency for preventing skeletal-related events in patients across a broad range of solid tumors. In addition, bisphosphonates, notably ZOL, prevent cancer treatment-induced bone loss in breast and prostate cancer patients who are receiving endocrine therapy. It also has been demonstrated that ZOL directly and indirectly inhibits cancer cell growth in vitro and growth and tumorigenesis in animal model systems. These properties may produce clinically meaningful benefits. In recent clinical studies in patients with cancer, ZOL improved overall and prolonged disease-free survival. Ongoing clinical trials in patients with solid tumors will provide further insight into the potential of ZOL to prevent distant metastases and improve survival. Cancer 2011. © 2010 American Cancer Society.