Aim To provide a critical review of research on clinical handover between the ambulance service and emergency department (ED) in hospitals. Method Data base and hand searches were conducted using the keywords ambulance, handover, handoff, emergency department, emergency room, ER, communication, and clinical handover. Data were extracted, summarised and critically assessed to provide evidence of current clinical handover processes. Results From 252 documents, eight studies fitted the inclusion criteria of clinical handover and the ambulance to ED patient transfer. Three themes were identified in the review: (1) important information may be missed during clinical handover; (2) structured handovers that include both written and verbal components may improve information exchange; (3) multidisciplinary education about the clinical handover process may encourage teamwork, a shared common language and a framework for minimum patient information to be transferred from the ambulance service to the hospital ED. Conclusion Knowledge gaps exist concerning handover information, consequences of poor handover, transfer of responsibility, staff perception of handovers, staff training and evaluation of recommended strategies to improve clinical handover. Evidence of strategies being implemented and further research is required to examine the ongoing effects of implementing the strategies.