This guideline covers organisational and managerial approaches to safe nurse staffing of inpatient wards for people aged 18 and over in acute hospitals. It aims to ensure that patients receive the nursing care they need, regardless of the ward to which they are allocated, the time of the day, or the day of the week. The guideline focuses on wards that provide overnight care for adult patients in acute hospitals. It does not cover intensive care, high dependency, maternity, mental health, acute admission or assessment units or wards, or inpatient wards in community hospitals.