A variety of new pharmacologic agents has allowed expanded therapeutic options for men with benign prostatic hypertrophy as well as men with prostate cancer. Appropriate implementation of these agents requires an understanding of their mechanisms of action, as well as awareness of the underlying pathological processes. Medical therapy of BPH is less invasive than standard surgical intervention, but it carries the risks of missing clinically significant prostate cancers. In addition, medical treatment of BPH is less effective than prostatectomy; however, since symptomatic relief is usually the end point of treatment for BPH, medical therapy is successful for many men without the risks of surgery. The GnRH agonists (and GnRH antagonists to be developed) allow medical hormonal therapy to be implemented for men with symptomatic prostate cancer without the psychological effects of castration. Oral antiandrogens allow for a prompt blockade of androgen action on prostate cancer during GnRH agonist use, and they may improve longevity for some men with prostate cancer. The widespread use of these agents should be tempered by their relatively high costs with long-term use.