The aim was to explore the comorbidity between Angelman syndrome and autism spectrum disorders (ASDs). Identification of autism in children with Angelman syndrome presents a diagnostic challenge. In the present study, 16 children with Angelman syndrome, all with a 15q11-13 deletion, were examined for ASDs. Thirteen children with Angelman syndrome received an ADOS-G algorithm classification of ASD; the remaining three were outside the autistic spectrum. Ten fulfilled the criteria for autism, and three for PDD-NOS. The 10 children with Angelman syndrome and comorbid autism were compared with eight children with only autism regarding their social and communicative skills. The results indicated that Angelman syndrome is better understood in terms of developmental delay, and autism in terms of developmental deviance. It is concluded that autism might have been overdiagnosed due to the extremely low mental age of the children with Angelman syndrome.