Purpose. To investigate the incidence, clinical presentation and associated comorbidities of Angelman syndrome ( AS) in Western Australia, with establishment of an information database for the disorder.Methods. Data were collected from Disability Services Commission files, supplemented by datasets provided by the Western Australian Data Linkage Unit. The analysis was retrospective and quantitative.Results. Thirty-four individuals ( two deceased) were identified ( 19 F, 15 M), with a mean age of 21.6 years; 52.9% had an IQ < 40, with the remainder of IQ 40 - 69. The incidence was one in 40,000 births and mean age at diagnosis was 5.8 years. The mean age of the 23 home residents was 20.2 years compared to 27.9 years in the nine individuals in sheltered accommodation. In general, the patients exhibited a typical AS clinical presentation. A median of 5.5 ( range 0 - 20) hospital admissions was recorded per person, with epilepsy, gastrointestinal disorders, and dental work all common reasons for admission.Conclusions. The estimated incidence was low compared to other reports, as was the proportion of IQ < 40. AS cases required substantial levels of medical care, especially those who were epileptic. An increase in the future numbers of AS patients needing sheltered accommodation is predicted.