The objective was to study the epilepsies of adults with Angelman syndrome (AS), and compare with the epilepsies of AS children and adolescents. AS is characterized by mental and motor neurodevelopmental arrest at a 1 year old level, resulting in the Happy Puppet phenotype. Published anecdotal reports of the epilepsy of AS indicate that adults do not have seizures. We performed 48 h of CCTV-EEG in 12 patients with AS. Two adult patients, AS7 (37 year old female) and AS27 (47 year old female) were compared with 10 children and adolescents. AS7 has a normal EEG background with 12 Hz well-modulated posterior rhythms. During sleep, frequent 1.5 Hz spike and slow wave formations are seen. AS27 also has a normal EEG background. She had hundreds of absence seizures lasting 3-12 s, characterized by arrest of activity and whole body shiver . The corresponding EEG shows bursts of diffuse 2.5-3 Hz, 400 μV irregular spike and slow waves. The child and adolescent with AS have EEGs reminiscent of infancy with slow high amplitude background. They have multiple absences. By adulthood, the brain seems to mature to allow a normal EEG background. Nevertheless, the adult patient can still have multiple undetected absences.