Although once reserved for the management of metastatic prostate cancer, androgen deprivation therapy (ADT) is being used increasingly to treat lower stages of disease. We sought to assess patterns of ADT use in a contemporary cohort of men newly diagnosed with prostate cancer. Men with newly diagnosed prostate cancer who had > or =12 months of follow-up evaluation were identified in a national disease registry of patients with prostate cancer. The patterns of ADT use, both primary and secondary, were characterized and stratified by risk according to prostate-specific antigen levels, clinical stage, and Gleason score. In a cohort of 1485 men, 46% underwent ADT at some point during their treatment: 41% as primary therapy (either sole therapy or neoadjuvant therapy), and 5% as secondary therapy. In all, 50% of men receiving initial ADT had low- or intermediate-risk disease characteristics. Among patients treated with radical prostatectomy and radiation therapy, neoadjuvant ADT was administered in 20% and 48% of patients, respectively. Secondary hormonal manipulation was observed in 5% and 7% of patients treated initially with surgery or radiation, respectively. ADT is commonly used to treat men with prostate cancer. Much of the use of ADT is in men with low- and intermediate-risk disease characteristics. The appropriateness of such therapy requires further study, including its effect, not only on disease endpoints, but also on resource utilization and health-related quality of life.