Several prospective randomized clinical trials have demonstrated improved outcomes in men receiving androgen deprivation therapy (ADT) in combination with definitive local therapy (external-beam radiotherapy or surgery). ADT is commonly combined with prostate brachytherapy (PB) to "downsize" the prostate gland. As PB is increasingly used, more men are being treated with a combination of ADT and PB. The purpose of this article is to review the effects of ADT in men treated with PB. A structured literature review was performed. The effects of ADT on 3 separate outcomes were examined: (1) volume of the prostate gland, (2) treatment-related morbidity, and (3) disease-free survival. No prospective randomized trials addressing the effects of ADT combined with PB were discovered. There is evidence that prostate volume is reduced by 25% to 40% after 3 months of ADT. There is some evidence that ADT may be associated with increased acute urinary morbidity and decreased erectile function after PB. There is little evidence that disease-free survival in men treated with PB is improved with the addition of ADT. Neoadjuvant ADT before PB reduces prostate volume. ADT may lead to increased acute urinary morbidity and decreased erectile function after PB. No substantial effects of ADT on disease-free survival are apparent. Prospective randomized trials of PB and ADT are required.