The assessment and management of clients with mental illness is an important facet of providing emergency care. In Australian emergency departments, it is usually the generalist registered nurses* without adequate preparation in the assessment and care for clients with mental illness who conduct the initial assessment at triage. A search of the literature revealed a limited number of publications addressing the provision of triage and management guidelines to assist nurses to make objective clinical decisions to ensure appropriate care for clients with mental illness. This paper examines the need for such guidelines and reviews a number of mental health triage scales that have been evaluated for use in emergency departments. Findings show that these triage scales have led to improvements in staff confidence and attitudes when dealing with clients with mental health problems, resulting in improved outcomes for clients. Strengths and limitations of the evaluations have also been explored. Highlighted is the need for consideration of the inclusion of clients’ reactions to the impact of this change to service delivery in future evaluations.