OUTLINE: This is a randomized, double blind, placebo controlled, open label, multicenter study. Patients are stratified by prior local treatment (noncurative vs curative) and time interval between surgical castration or initiation of LHRH agonists and trial entry (less than 1 year vs 1-2 years vs greater than 2 years). Patients are randomized to 1 of 2 treatment arms: Arm I: Patients receive zoledronate IV over 15 minutes on day 1. Arm II: Patients receive placebo IV over 15 minutes on day 1. Both arms: Treatment repeats every 4 weeks in the absence of documented bone metastasis, disease progression, or unacceptable toxicity. All patients with documented bone metastases receive zoledronate as in arm I through year 4. All patients receive oral calcium and oral vitamin D daily. Patients who received LHRH agonists instead of surgical castration prior to study continue LHRH agonist therapy during study. Quality of life and pain are assessed before each treatment. Patients are followed every 6 months.