While there is a deficiency in the number of randomized control studies dealing with the pharmacologic control of the ventricular response to atrial fibrillation (AF) or atrial flutter (AFL) after cardiac surgery, evidence-based recommendations are presented from those studies that are available. Because of the hyperadrenergic state after surgery, beta-blockers are recommended as the first line of therapy for patients with AF or AFL who do not require urgent cardioversion. Calcium channel blockers are recommended as second-line therapeutic agents. Digoxin has little efficacy because of the heightened adrenergic tone that is present postoperatively. Agents that are proarrhythmic, such as dofetilide, or agents that are contraindicated in patients with coronary artery disease, such as flecainide and propafenone, are not recommended.