Emergency care services in the UK are receiving increasing numbers of patients presenting with a wide range of problems, from life-threatening conditions to minor injury or illness. All patients seeking emergency care need to be assessed and classified to prioritise those who have the most urgent problems and are in need of immediate care. This article provides an overview of triage within an emergency care setting. It explores the development of triage and describes the nationally recognised Manchester Triage System. The professional and legal responsibilities of the triage nurse are also discussed.