An understanding of prognosis in cancer medicine is important for patient care, research and cancer control programs. In prostate cancer, prognostic (predictive) factors are particularly important given the marked heterogeneity of this disease at clinical, morphologic and biomolecular levels. Clinical stage and histologic grade have historically played major roles in defining heterogeneity in prostate cancer. More recently, serum prostate-specific antigen measurement has assumed a significant prognostic role. Over the last two decades there has been an explosion of research into biomarkers, many of which have been purported to have prognostic significance. In this paper we present an overview of the various consensus initiatives that have transpired over the last dozen years. Criteria for evaluating prognostic factors and classifications of predictive factors have emerged that have proven useful and advanced our understanding of the biology of prostate cancer. The results of these consensus initiatives form a foundation on which the current international consultation on prognosis (prediction) in prostate cancer is built. Advances in our understanding of the new and promising prognostic factors will require a more rigorous evidence-based approach to the analysis of published studies. Furthermore, appropriate mathematical models for the analysis of the multiple factors that influence a prognostic system will have to be employed.