The aim of the study was to provide an overview on the current evidence on the method of cardioversion in patients presenting with recent-onset atrial fibrillation at the emergency department. ISI Web of Science and MEDLINE were explored for articles published between January 2000 and December 2011 in English or Spanish for the keywords 'acute', 'recent-onset' or 'paroxysmal' AND 'atrial fibrillation' AND 'treatment' AND 'emergency'. Original published articles were included if they enrolled patients with atrial fibrillation episodes of short duration (<48 h) and if they specifically addressed time to conversion, length of stay in the emergency department, safety, and/or relapses. Data extracted included the number of patients included, agent(s) studied, type and level of evidence of the article, rate of sinus rhythm conversion, time to conversion, discharge rate, length of stay, adverse events, embolic complications, and relapses. Fourteen papers were included in the review, eight of them prospective and randomized. Cardioversion in the emergency department had an overall high rate of conversion and few side-effects and/or embolic complications. Direct current cardioversion was the most effective therapeutic strategy in terms of sinus rhythm restoration, rate of discharge, length of stay, and safety. Class I drugs were also effective in a selected population. Amiodarone had a longer conversion time, with a similar rate of acute adverse events. Cardioversion in the emergency department is feasible and safe. Direct current cardioversion is the most effective therapeutic strategy.