Monoamine oxidase (MAO) deficiency is an X-linked hereditary disease characterized by spontaneous deletion of MAO-A and/or MAO-B on the X chromosome. Here, we describe the first reported case of a patient with MAO-A and MAO-B deficiency managed under general anesthesia in dental treatment. The patient was aged 11 years old when he was scheduled for dental treatment. He was diagnosed with MAO-A and MAO-B deficiency on genetic testing at 2 years of age. He was not given premedication, and standard monitoring with noninvasive blood pressure monitoring, pulse oximetry, and ECG was instituted. We also preemptively prepared a cardioverter-defibrillator. General anesthesia was induced with propofol 46 mg (2 mg/kg), then rocuronium 10 mg (0.4 mg/kg) and remifentanil 0.30 μg/kg/min were administered via separate infusion pumps. Orotracheal intubation was performed without complications. Anesthesia was maintained uneventfully with a continuous infusion of remifentanil 0.15-0.2 μg/kg/min and propofol 5.0-7.0 mg/kg. Fresh gas flow included oxygen and air. End-tidal CO2 concentration was maintained at around 35 mmHg throughout the procedure. We administered sugammadex 92 mg (4 mg/kg) for reversal of neuromuscular blockade and the patient was extubated. We achieved successful anesthetic management without any appreciable clinical signs of fatal arrhythmias in this patient with MAO-A and MAO-B deficiency.