Recent guidelines on cancer screening have provided not only more screening options but also conflicting recommendations. Thus, patients, with their clinicians' support, must decide whether to get screened, which modality to use, and how often to undergo screening. Decision aids could potentially lead to better shared decision-making regarding screening between the patient and the clinician. A total of 73 decision aids concerning screening for breast, cervical, colorectal, and prostate cancers were reviewed. The goal of this review was to assess the effectiveness of such decision aids, examine areas in need of more research, and determine how the decision aids can be currently applied in the real-world setting. Most studies used sound study designs. Significant variation existed in the setting, theoretical framework, and measured outcomes. Just over one-third of the decision aids included an explicit values clarification. Other than knowledge, little consistency was noted with regard to which patient attributes were measured as outcomes. Few studies actually measured shared decision-making. Little information was available regarding the feasibility and outcomes of integrating decision aids into practice. In this review, the implications for future research, as well as what clinicians can do now to incorporate decision aids into their practice, are discussed. CA Cancer J Clin 2013. © 2013 American Cancer Society.