Fetal atrial flutter (AF) is the second common fetal tachyarrhythmias that exist in less than 1% of all pregnancies. It may be related to congestive heart failure, hydrops, neurologic morbidity, or intrauterine death. Early detection and treatment are crucial for getting better neonatal outcomes. We presented a case of fetal atrial flutter diagnosed in the 36th week of gestation and managed successfully by cardioversion in the postpartum period. Cardioversion could be carried out successfully for the treatment of atrial flutter especially in arrhythmias resistant to antiarrhythmic medication during the immediate postpartum period. The recurrence rate of AF after this procedure is very low.