Purpose of Review: The autonomic nerve system is a potentially potent modulator of the initiation and perpetuation of atrial fibrillation. This review will briefly summarize the neural mechanisms of atrial fibrillation. Recent Findings: Complex interactions exist between the sympathetic and parasympathetic nervous system on the atrial electrophysiologic properties. Direct autonomic recordings in canine models demonstrated simultaneous sympathovagal discharges are the most common triggers of paroxysmal atrial tachycardia and paroxysmal atrial fibrillation. Also, intrinsic cardiac autonomic nerve can serve as a sole triggering factor for the initiation of atrial fibrillation. Modulation of autonomic nervous system (ANS) by electrical stimulation has been tried as a treatment strategy clinically and experimentally. Recent studies showed that autonomic nervous system modulation can suppress the stellate ganglion nerve activity and reduce the incidence of paroxysmal atrial tachyarrhythmias in ambulatory dogs. Summary: The autonomic nerve system influences the initiation and perpetuation of atrial fibrillation. Scientific advances toward a better understanding of the complex interrelationships of the various components of the ANS will hopefully lead to improvement of treatments for this common arrhythmia.