Besides a palliative role, current clinical and preclinical data suggest that a bone targeted approach may represent a potentially useful component of the overall therapeutic approach for metastatic prostate cancer. Randomized, double-blind, placebo controlled trials suggest that bisphosphonates and endothelin A antagonists may delay the progression of prostate cancer in bone. These clinical observations of relatively large trials have provided impetus for the design of large definitive studies to evaluate the role of various bone targeted approaches for the treatment of prostate cancer.