Prostate cancer is an excellent target for prevention, to reduce both mortality and the burden of overdetection of potential inconsequential disease whose diagnosis increases cost, morbidity, and anxiety. The Prostate Cancer Prevention Trial has demonstrated that finasteride significantly reduces the risk of prostate cancer but only low-grade disease; overall survival is unaffected. In the Selenium and Vitamin E Cancer Prevention Trial (SELECT) clinical trial, selenium had no effect on prostate cancer risk, but alpha tocopherol significantly increased the risk by 17%. The most promising future approaches to prostate cancer prevention will likely focus on nutrition, especially weight control, and through modulation of inflammation.