In 2001 a mental health triage scale was introduced into the emergency department of the Geelong Hospital, Victoria. Changes were made to the assessment and management of clients with a mental illness by mental health and emergency triage staff. The new service has been used as a model of contempory service delivery across Victoria. Since the introduction of this model it is evident misunderstanding exists as to the nature and principles of emergency triage by some mental health triage staff. This presentation presents the principles of emergency triage from a historical and current policy perspective. Exemplars of the parallels between physical and metal illness in the context of emergency triage and the variety of models of mental health care for clients with a mental illness in the emergency department are presented. As well as this the conflicts in terminology that exist within emergency department practice and mental health practice in relation to mental health triage are detailed and explained. This paper details the important principles of emergency triage and examines them in the context of contempory mental health service delivery to clients with a mental illness in the emergency department.