Major trauma centres provide specialised care for patients who have experienced serious traumatic injury. This article provides information about major trauma centres and outlines the assessment tools used in this setting. Since patients in major trauma centres will be transferred to other settings, including inpatient wards and primary care, this article is relevant for both nurses working in major trauma centres and in these areas. Traumatic injuries require rapid assessment to ensure the patient receives prompt, adequate and appropriate treatment. A range of assessment tools are available to assist nurses in major trauma centres and emergency care to assess the severity of a patient’s injury. The most commonly used tools are triage, Catastrophic Haemorrhage Airway to Exposure assessment, pain assessment and the Glasgow Coma Scale. This article summarises the use of these assessment tools in these settings, and discusses the use of the Injury Severity Score (ISS) to determine the severity of patient injuries.