The Angelman syndrome is characterized by an abnormality of chromosome 15, where a subunit of the gamma amino-butyric acid receptor is coded. The clinical features are developmental delay, microcephaly, wide mouth, prognathia which usually do not have problem with intubation. But, muscular atrophy may induce delayed recovery from neuromuscular blockade. Moreover, there are case reports that vagal hypertonia such as severe bardycardia or asystole occurred during anesthesia. We present a 5-year-9-month-old male Angelman syndrome patient who underwent a left and right rectus ophthalmicus muscle recession. We gave him prophylactic glycopyrrolate before anesthetic induction and induced and maintained anesthesia with sevoflurane and oxygen. After that we monitored train-of-four ratio for evaluation of neuromuscular blockade. There is no complication during operation and recovery from anesthesia.