The incidence of conjoined twins is so rare that few anesthesiologists have an opportunity of managing them. Especially in Korea, there are only a few reports describing the anesthetic management for surgical separation of newborn conjoined twins. We experienced the successful anesthetic management for surgical separation of thoraco-xiphopagus conjoined twins without any particular problems. After applying the noninvasive monitors (ECG, pulse oximeter), one of the twins (twinA) with congenital heart disease was administered with intravenous ketamine for induction of anesthesia and intubated without neuromuscular blocker. Anesthesia was maintained with N2O-O2 and hand ventilation using Mapleson D breathing circuit. After maintaining airway of the twinA, the twinB was intubated and maintained with the same manner. Eighteen days after the separation procedure, the twinA with congenital heart disease died and the other one, twinB has been alive with normal growth and development.