The aim of this study was to determine the treatment patterns and resource utilization of various prostate cancer treatments, and quantify the economic and clinical impact of each. In a retrospective analysis of medical and pharmacy claims between 2000 and 2005, using the PharMetrics database, male patients aged > or =40 years with prostate cancer diagnosis were identified. The costs of medical and prostate cancer-related expenditures for the treatment options were determined for three periods: from diagnosis to first treatment, during and after treatment. A total of 9035 patients were included. The mean age of patients diagnosed with prostate cancer was 61.4 years. Patients aged 50-59 years represented the highest proportion at 51%. The majority received some form of treatment. Watchful waiting (WW) was the primary means of management for 30%. The average 2-year cost for WW was $24 809 and for active treatment was $59, 286. Surgery was the most common treatment among younger men. Non-cancer-related costs were similar among those receiving treatment or WW, but prostate cancer costs were over five times greater in the treated patients. With or without treatment, prostate cancer is a significant clinical and economic burden to society. New strategies for treatment or cancer prevention could play a role in reducing this burden.