Bone is the most common site of metastases from breast and prostate cancer, and bone destruction is characteristic of multiple myeloma. Increased osteoclast activity plays a key role in cancer-induced bone destruction. Bisphosphonates reduce osteoclastic bone resorption through various mechanisms as yet not fully elucidated. Bisphosphonates have proven to be effective in the treatment of tumor-induced hypercalcaemia. Several clinical trials indicated that these compounds can positively influence many aspects of neoplastic bone disease, however, many questions regarding their long-term efficacy and optimal therapeutic schedule await clarification from well-designed clinical trials.