Atrial fibrillation (AF) is a common cardiac arrhythmia associated with an increasing prevalence with advancing age. It is associated with dyspnea, exercise intolerance, and increased risk for clinical events, especially stroke and heart failure. This article provides a concise review of exercise testing and rehabilitation in patients with persistent or permanent AF. The first goal in the treatment of AF is to reduce symptoms (eg, palpitations) and a fast ventricular rate. The second goal is to reduce the risk of a stroke. Exercise testing and rehabilitation may be useful once these goals are achieved. However, there are no large, randomized exercise training trials involving patients with AF, and what data are available comes from single-site trials, secondary analyses, and observational studies. There are no specific indications for performing a graded exercise test in patients with AF; however, such testing may be used to screen for myocardial ischemia or evaluate chronotropic response during exertion. Among patients with AF, exercise capacity is 15% to 20% lower and peak heart rate is higher than in patients in sinus rhythm. Exercise rehabilitation improves exercise capacity, likely improves quality of life, and may improve symptoms associated with AF. Whole-body aerobic exercise is recommended. Atrial fibrillation is a common cardiac condition and in these patients, exercise rehabilitation favorably improves exercise capacity. However, prospective randomized controlled trials are needed to better define the effects of exercise training on safety; quality of life; clinical outcomes; and central, autonomic, and peripheral adaptations.