Risk stratification in prostate cancer was originally defined to describe the chances of biochemical relapse in patients with localized disease based on clinical stage, Gleason’s score, and preoperative prostate specific antigen levels. High risk was defined as 5-year risk of biochemical failure exceeding 50%. Over the last three decades, this risk stratification has been refined, and outcomes with several treatment strategies have been defined with improvement in treatment techniques and newer systemic therapy agents. This chapter describes this evolution and outlines future directions incorporating personalized treatment strategies.