The primary objective of this study is to determine whether zoledronic acid (Zometa) given once annually increases bone mineral density in men receiving hormone therapy for prostate cancer.

• Patients will be randomized into 2 groups. At the screening visit, a bone mineral density test will be performed to determine if the patient has osteoporosis or not. Patients with osteoporosis will be treated with Zometa. Patients without osteoporosis will be randomly assigned to receive either Zometa or a placebo.
• Zometa is administered intravenously over a 15 minute prior once in this one year study.
• All patients will asked to take an over-the-counter oral calcium (500mg daily) and a daily multi-vitamin (containing 400-500 I.U of vitamin D) during the study.
• All patients will have clinic visits every 3 months for blood tests and to report any side effects they may be experiencing. At month 12, a bone mineral density test will be repeated.

Inclusion Criteria:

• Adenocarcinoma of the prostate
• Current androgen deprivation therapy with expected duration of treatment greater than or equal to 12 months
• Corrected serum calcium > 8.4mg/dl and < 10.6mg/dl
• Serum creatinine < 2.0mg/dl

Exclusion Criteria:

• History of bone metastases by bone scan
• Treatment with bisphosphonate within one year
• History of metabolic disease
• Chronic use of glucocorticoids, anticonvulsants, or suppressive doses of thyroxine within one year