Autism and the other disorders in the autism spectrum are behaviorally defined syndromes that can be a prolonged disorder. The specific underlying neurophysiologic mechanisms simply not known, but probably several causes lead to disorders in the autism spectrum. This article is summary of recent research about etiology of autism but the search must continue. 1) Neurobiological origin, the neurobiological investigations show the role of dopamine and serotonin in pathogenesis of autism. 2) Genetic, studies in autism was established the hypothesis that genetic factors can be etiologically significant in subsets of patients. 3) With the Regional cerebral glucose metabolism measurement, autistic children had a left> right anterior rectal gyrus asymmetry as opposed to the normal right> left asymmetry in that region. 4) With the Regional cerebral blood flow measurement no cortical regional abnormalities were found. 5) Association of epilepsy and autism pediatric epilepsy lead to autistic regression. 6) Association of tuberous sclerosis and autism the number of tubers was significantly greater in individuals with a diagnosis of autism than in those without this diagnosis. 7) Embryological origin for autism, the results and two new lines of evidence that place the initiating injury for autism around the time of neural tube closure. 8) Obstetric complications and later autistic disorder, these data do not support the view that obstetric complications increase the risk for later autism. 9) Food allergy, recent findings show a relationship between food allergy and infantile autism. 10) Head circumferences measurement in children with autism show the large head circumference and increased growth.