Wolff-Parkinson-White (WPW) syndrome is a cardiac conduction disorder that presents potentially life-threatening consequences, and it is important that anesthesiologists recognize this syndrome because the sudden development of tachyarrhythmias may result in deleterious hemodynamic changes. We report an episode of severe hemodynamic changes induced by the insertion of a guide wire during central venous cannulation and operation in a 62-yr-old female patient with WPW syndrome. Initially, unstable paroxysmal supraventricular tachycardia was developed during central venous cannulation, which was disappeared immediately upon removing the guide wire. Subsequently, paroxysmal supraventricular tachycardia with severe hemodynamic changes developed 2 hours after operation, and this was successfully treated with an intravenous injection of adenosine, deep anesthesia with sevoflurane and fentanyl, and dopamine infusion. The patient recovered uneventfully after the operation.