Assessment of elder mistreatment is hindered by a myriad of factors, including inconsistent definitions, divergent and untested theories of causation, and limited research attention to the problem. In addition to these difficulties, professionals encounter complex situations requiring considerable clinical assessment skills and decision-making capacity. Adult Protective Services (APS) workers, as well as mandated reporters such as healthcare providers and social workers, need an assessment tool that can reliably and accurately assess for elder mistreatment. Based on a structured review of screening and assessment instruments, this article discusses the psychometric properties of 15 instruments and the relevance to APS. Implications of the findings for future research, practice, and policy are discussed.