Treatment decision-making can be difficult and complex for patients with low-risk prostate cancer. To the authors' knowledge, there is no consensus regarding an optimal treatment strategy and the choice of therapy involves tradeoffs between differing harms and benefits that are sensitive to patient values. In such situations, patients are often asked to participate actively in the decision-making process, and high-quality decisions require a well-informed patient whose values and preferences have been taken into consideration. Prior studies have indicated that patients have poor knowledge and unrealistic expectations regarding treatment, and physician judgments concerning patient preferences are often inaccurate. Decision aids (DAs) have been developed to help inform patients with low-risk prostate cancer about treatment options and assist in the decision-making process; however, little is currently known regarding the effects of such programs in this population. Thirteen studies of DAs for patients with prostate cancer were reviewed and it was found that the use of DAs can improve knowledge, encourage more active patient involvement in decision-making, and decrease levels of anxiety and distress. The effect of DAs on treatment choice was less clear, although fewer patients chose surgery compared with historical controls, particularly in Europe. Further studies are needed to determine how best to implement DAs into practice, and whether they improve the consistency between patient preferences and treatment choice. CA Cancer J Clin 2009. © 2009 American Cancer Society, Inc.