The category of pervasive developmental disorders (PDD) includes autistic disorder, Rett syndrome, disintegrative disorder, Asperger's syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS). DSM-V uses a unique term – autism spectrum disorders – for a group of disorders similar to autism, which were called pervasive developmental disorders according to DSM-IV. The correct cause of the disorders is not yet known, so it is often said that there is multicausality of the etiology of autism spectrum disorders. Signs which indicate the autistic spectrum disorder are difficult to recognize. The criteria for the diagnosis of an autistic disorder are the beginning of the disorder during the childhood, social interaction, communication, and limited interests. Nowadays, there is an increasing number of children with an autism spectrum disorder who show remarkable abilities in some narrow field. These children are called idiot-savant or autistic savant. After the diagnosis is established, a suitable treatment method needs to be developed. Many methods proved successful in the treatment of an autism spectrum disorder. None of them is to be said to completely cure the disorder, but they can rather lead to a significant improvement. For the development of the treatment, individual abilities, peculiarities, and needs of every child with an autism spectrum disorder must be assessed with the help of psychometric tests. Children with an autism spectrum disorder mostly attend full-time kindergarten programs, where an educator is a crucial factor. Educators need to adapt the space and materials to the children's needs, as well as cooperate with parents to affect the child's progress. The diagnosias of disorders affects the entire family, who have difficulty dealing with a new life situation and the changes it brings about. Therefore it is important to show support and understanding for the parents and siblings of a child diagnosed with an autism spectrum disorder in order for them to adapt more easily and to be able to help their autistic child