A 71-year-old woman with a history of persistent atrial fibrillation underwent clipping of a ruptured cerebral artery aneurysm. During the surgery her cardiac rhythm was atrial fibrillation and the ventricular rate increased to 130 beats.min(-1). Administration of landiolol was started with 1-min loading infusion at 0.125 mg.kg(-1).min(-1) and continuous infusion at 0.04 mg.kg(-1).min(-1), which was effective in controlling the ventricular rate without causing hypotension. Approximately 120 min after the landiolol infusion was started, the atrial fibrillation was converted to sinus rhythm. Her sinus rhythm was maintained until she left the operating room, even after discontinuation of landiolol.