More than 400,000 patients undergo coronary artery bypass graft surgery (CABG) each year in the United States. At least 20-30% of these patients have atrial fibrillation (Afib), making this arrhythmia one of the most common postoperative problems. This generally benign problem can increase surgical morbidity and the cost and length of hospital stay. If not treated promptly and effectively, Afib can delay a full and rapid recovery. Afib usually occurs in paroxysms between the second and fifth postoperative day and appears directly related to effects of surgery (pericarditis, changes in autonomic tone, cardioplegia, myocardial damage, fluid shifts, etc.). Although similar to Afib in other settings, beta-adrenergic blockade is more effective in preventing and terminating Afib in the postoperative setting. The unique circumstances that precipitate postoperative Afib may explain the favorable therapeutic and prophylactic actions of beta-adrenergic blockade. Other therapies such as amiodarone, sotalol, and digoxin are surprisingly ineffective for postoperative Afib, while intravenous diltiazem is not well tested in this setting. Despite the lack of proven benefit for some of these therapies, they are still frequently used in current clinical practice. Management of postoperative Afib is initially directed at ventricular rate control, but the ultimate goal is return to sinus rhythm. The approach to therapy depends on several clinical variables, including the time course of the arrhythmia, but hemodynamic stability of the patient is the key issue. Return to sinus rhythm may be difficult to achieve early after surgery, so opting for rate control is the best initial approach. If tolerated, beta-adrenergic blockade and calcium antagonism are the best first options. Class IA and III antiarrhythmic drugs should be reserved for persistent or poorly tolerated and prolonged episodes of Afib. Elective cardioversion, either by direct current or with drugs, should be delayed for as long as possible after surgery. Anticoagulation for post-CABG Afib remains controversial. More prudent use of presently available drugs to treat Afib could reduce morbidity, cost, and duration of hospital stay after CABG. More rapid-acting and reliably effective antiarrhythmic therapies with minimal adverse effects would greatly improve management of post-CABG Afib.