Angelman syndrome is the consequence of a genetic alteration in the chromosome 15 where the expression of the β3-subunits of GABA-A receptors is encoded. So, unpredictable responses to intravenous GABA-anesthetics may be the result. We present a 19-year-old male patient with AS who required anesthesia to undergo an MRI and CT-scan. All his previous anesthetic procedures were complicated by severe emergence agitation with physical self-injury. His parents also mentioned that the patient reacted with paradoxical agitation due to benzodiazepines (midazolam) administration in previous anesthesia. Dexmedetomidine (an α-2- adrenergic agonist) has been used in pediatric anesthesia as an adjuvant to attenuate agitation events after inhalation anesthesia. However, there are few publications on its use in patients with AS. We describe the use of a single intravenous dose of dexmedetomidine (0.2μg/Kg) to prevent sevoflurane-related emergence agitation with good results.In addition, the potential benefits and precautions in using this non-GABA drug in patients with AS are discussed.