The prevalence of obesity is growing at alarming rate worldwide. Obesity has reached the proportion of a global epidemic in both developed and developing countries. Growing number of obese patients with atrial fibrillation requires a closer look at how excessive body fat leads to AF. Excessive adipose tissue is the source of many cardiovascular diseases, like hypertension, ischemic heart disease, and arrhythmias such as atrial fibrillation. The prevalence of atrial fibrillation in the general population is estimated at 1-2%. Obesity and overweight occur in 25% of patients with AF. Pathophysiology of obesity and the relationship between atrial fibrillation, diabetes, obstructive sleep apnea and metabolic syndrome are presented in this article as well as the benefit of bariatric surgery in qualifying patients. Paroxysmal AF and its risk factors should be carefully assessed in all patients referred for bariatric surgery. Proper diagnosis allows physicians to introduce appropriate anticoagulant prophylaxis, and significantly lower complication rate. Antiarrhythmic, respiratory, and metabolic therapy should also be considered in preoperative and postoperative care.