A 23-year-old woman with craniofacial hyperhidrosis underwent bilateral thoracoscopic T2-sympathectomy. Marked sinus bradycardia with a mean heart rate of 49 beats/min by Holter ECG monitoring occurred after the procedure and persisted for > 2 years. Normal sinus node function was found by an invasive electrophysiological study and unopposed vagotonia after sympathectomy was diagnosed. A permanent pacemaker was implanted. Although reduced heart rate is a common phenomenon after bilateral dorsal sympathectomy, intractable bradycardia with permanent pacing is rare. This patient demonstrates one of the potential cardiac complications of bilateral sympathectomy.