The prevalence of autistic disorder was analysed in 25 individuals with Möbius sequence, a disorder with brain-stem dysfunction. The sample consisted of 18 males and seven females (20 participants were aged 2 to 22 years, and five were aged 1, 19 and 23 months, and 55 years old). Participants were recruited after a nationwide call and were part of a multidisciplinary study of individuals with Möbius sequence. They were given a meticulous neuropsychiatric examination including standardized autism diagnostic interviews. Ten individuals had an autistic spectrum disorder. Six of these met all diagnostic criteria for autism. In 23 individuals cognitive development could be assessed. Eight of those 23 patients had clear learning disability and six individuals were functioning in the normal but subaverage range. Autistic spectrum disorder and learning disability occurred in more than a third of the examined patients. Considering the hospital-based nature of the sample, these findings may be overestimates. Nevertheless, awareness of this coexistence is important in the diagnosis and habilitation care of children with Möbius sequence. Moreover, the results provide further support for the notion of a subgroup of autistic spectrum disorders being caused by first trimester brain-stem damage.