Accurate assessment of the acutely ill adult who has recently been admitted to hospital, or an inpatient whose condition begins to deteriorate, is becoming a required skill for nurses as people live longer and with a variety of complex conditions, and as nursing skills continue to evolve and develop. This article emphasises the importance of undertaking an accurate and comprehensive patient assessment to ensure that management strategies are implemented in a timely manner. The article also considers the importance of the National Early Warning Score (NEWS), which is a ‘track-and-trigger’ tool designed to identify patients who are at risk of deterioration. The presentation of shock is considered and how this can be identified using the NEWS. The patient assessment skills required by nurses are discussed and the main signs of patient deterioration, regardless of cause, are outlined. The article also examines the ABCDE (airway, breathing, circulation, disability and exposure) approach to assessment.