The Prostate Cancer Intervention Versus Observation Trial (PIVOT) is a randomized trial designed to determine whether radical prostatectomy or expectant management provides superior length and quality of life for men with clinically localized prostate cancer. Conducted at Department of Veterans Affairs and National Cancer Institute medical centers, PIVOT will enroll over 1,000 individuals < 75 years of age. The primary study end point is all-cause mortality. Secondary outcomes include prostate cancer- and treatment-specific morbidity and mortality, health status, predictors of disease-specific outcomes, and cost-effectiveness. Within the first 3 years of enrollment, over 400 men have been randomized. Early analysis of participants' baseline characteristics indicate that enrollees are representative of men diagnosed with clinically localized prostate cancer throughout the United States. Therefore, results of PIVOT will be generalizable. These results are necessary in order to determine the preferred therapy for clinically localized prostate cancer.