Atrial fibrillation (AF) is a common, benign, and transient type of supraventricular arrhythmia encountered during the early postoperative period after a pulmonary resection. However, it sometimes might result in hemodynamic deterioration. We report on a case of new-onset atrial fibrillation in a 74-year-old male patient after right lower lobectomy, which was not controlled with intermittent bolus injection of esmolol and diltiazem. Successful pharmacological cardioversion was achieved with intravenous (6 mg/hr for 2 hours) followed by oral (90 mg q day) diltiazem 20 hours after this treatment. The literature on the risk factors and management of atrial fibrillation after pulmonary resection is reviewed.