OBJECTIVE We objectively compare the costs associated with the medical and surgical treatment of metastatic prostate cancer. METHODS We analyzed and compared itemized billing statements for 28 men with metastatic adenocarcinoma of the prostate. Half of the men were treated medically with the luteinizing hormone-releasing hormone analogue leuprolide, while the other half underwent bilateral therapeutic orchiectomy. In addition, differences in hospital cost to treat these men were calculated. RESULTS During a mean followup of 24 months leuprolide treated patients were charged $500.00 per month of treatment compared to average monthly expenditure of $226.00 for orchiectomy patients during a 23-month interval. By 9 months charges incurred by both groups were equal and by 20 months medically treated patients accumulated urological charges twice that of the surgically treated patients. The true hospital cost to treat these patients followed the same trend, that is the medically treated group cost twice as much to treat by 15 months. For the average stage D2 case leuprolide therapy charges were $9,420, or 63%, more than orchiectomy. Similarly, leuprolide cost the hospital $8,924 more than surgery. CONCLUSIONS Medical management of metastatic prostate cancer is expensive. With broadening applications and androgen deprivation being initiated earlier in the course of disease, the amount spent on medical therapy will continue to escalate. For patients with a life expectancy of more than 9 months orchiectomy is the most cost-effective treatment option.