Wolff-Hirschorn syndrome is a condition that is caused by a deletion of genetic material near the end of the short (p) arm of chromosome 4. The major features of this disorder include a characteristic facial appearance, delayed growth and development, intellectual disability, and seizures. A 9-year-old girl was brought to the clinic with a chief complaint of dental examination. The child was diagnosed as WHS at Samsung medical center. The child was under Sodium valproate, Atrovastatin medication for epilepsy, hyperlipidemia and had a history of heart surgery. So prophylactic antibiotics were recommended. The child was mentally retarded and had seizure so it was difficult to manage her behavior effectively. Thus dental treatment was carried out under general anesthesia. For prompt sedation induction we used 8% sevoflurane shortly. This report presents the case of a 9-year-old girl with WHS, who has received treatment for extensive caries under general anesthesia.