Atrial fibrillation (AF) is the most prevalent arrhythmia in hospital emergency departments and is a serious disease associated with a twofold increase in morbidity and a high mortality rate. However, the management of AF in this scenario is variable and frequently inadequate. This is probably a consequence of the diverse clinical aspects and therapeutic options to consider in the management of patients with AF. Therefore, implementation of specific, coordinated management strategies by the different care providers involved is needed to improve the quality of care and optimize the use of human and material resources. This document presents the guidelines recommended by the Spanish Society of Cardiology (SEC) and the Spanish Society of Emergency Medicine (SEMES) for the management of AF in hospital emergency departments. These guidelines are based on published scientific evidence and are applicable to most emergency departments in Spain. Specific management strategies are proposed for the conversion and maintenance of sinus rhythm, heart rate control during AF, prophylaxis for thrombi and emboli, and hospital admission and discharge protocols.