Atrial fibrillation (AF) is present in 5 percent of hypertrophic cardiomyopathy (HCM) patients at the time of diagnosis. Ostial pulmonary vein (PV) diameter is increased in patients with AF as well as hypertensive patients. These findings support the theory that the cascade of events leading to diastolic dysfunction might predispose a person to AF by stretching the PVs. This mechanism is likely relevant to AF in HCM as well. The recognition that AF often times arises from the PVs has led to innovation of ablation techniques that target this zone to electrically isolate the PVs from the left atrium (LA). Anticoagulation is the cornerstone of AF treatment. Additional AF treatment in HCM patients de- pends on the initial decision regarding need for surgical intervention, whether or not AF is permanent, and the severity of symptoms in pati- ents with non-permanent AF. If surgery is planned, correction of the arrhythmia with MAZE procedure, which isolates the arrhythmogenic foci, at the time of myectomy is an option to consider. The goal in HCM patients with permanent AF is to control the heart rate whether by chronic medications or through ablate + pace procedure. Based on the severity of symptoms, HCM patients with non-permanent AF will be treated with either the rate control strategy (β-blockers/calcium channel blocker) or the rhythm control strategy (PV ablation, antiarrhyth- mic drugs, or radiofrequency ablation of the LA). This is because adverse effects of antiarrhythmics and complications after invasive proce- dures are justifiable only in HCM patients who experience severe symptoms.