Aims. The aim of this study was to improve the emergency nursing care of acute stroke by enhancing the use of evidence regarding prevention of early complications. Background. Preventing complications in the first 24–48 hours decreases stroke-related mortality. Many patients spend considerable part of the first 24 hours following stroke in the Emergency Department therefore emergency nurses play a key role in patient outcomes following stroke. Design. A pre-test/post-test design was used and the study intervention was a guideline for Emergency Department nursing management of acute stroke. Methods. The following outcomes were measured before and after guideline implementation: triage category, waiting time, Emergency Department length of stay, time to specialist assessment, assessment and monitoring of vital signs, temperature and blood glucose and venous-thromboembolism and pressure injury risk assessment and interventions. Results. There was significant improvement in triage decisions (21Æ4% increase in triage category 2, p = 0Æ009; 15Æ6% decrease in triage category 4, p = 0Æ048). Frequency of assessments of respiratory rate (p = 0Æ009), heart rate (p = 0Æ022), blood pressure (p = 0Æ032) and oxygen saturation (p = 0Æ001) increased. In terms of risk management, documentation of pressure area interventions increased by 28Æ8% (p = 0Æ006), documentation of nil orally status increased by 13Æ8% (ns), swallow assessment prior to oral intake increased by 41Æ3% (p = 0Æ003), speech pathology assessment in Emergency Department increased by 6Æ1% (ns) and there was 93Æ5 minute decrease in time to speech pathology assessment for admitted patients (ns). Relevance to clinical practice. An evidence-based guideline can improve emergency nursing care of acute stroke and optimise patient outcomes following stroke. As the continuum of stroke care begins in the Emergency Department, detailed recommendations for evidence-based emergency nursing care should be included in all multidisciplinary guidelines for the management of acute stroke.