Radical treatment for prostate cancer aims at complete eradication of tumor. This review of published data makes clear that the goal is less frequently achieved than commonly presumed. Following radical prostatectomy extracapsular disease, carrying a significant risk of local recurrence, is found from 12-68% of the time depending on the clinical tumor stage. Local regrowth is associated with a poorer prognosis. A substantial proportion of patients whose prostate glands are rebiopsied more than 18 months after radiation therapy also have residual tumor. This again predicts for clinical relapse. The likelihood of a positive rebiopsy is dependent on original tumor size and current prostate specific antigen (PSA) levels. Strategies for managing residual disease are critically discussed.