Nowadays the combination of genetic predisposition with external factors is considered to be the etiologic reason of autistic disorders. They are viruses, various toxins, immune and allergic stress etc. the frequency of organic brain damage in the development of autistic disorders is not clear yet.

The aim of the investigation was to reveal structural malformations and actual organic brain damage in patients with autistic disorders. Were examined 61 children in the age of 3–15 years. Diagnosis based on DSM-IV criteria after detailed clinical and psychological investigation.

The results of MRI examination show following structural alterations. in 21 (34.4%) cases were founded consequences of brain structures infection; in 24 (39.3%) cases - signs of chronic inflammation in sinuses and temporal bones; in 8 (13.1%) cases were defined cysts of the brain's middle line; in 40 (65%) - hypertrophied adenoids. Only 12 (19.7%) of examined patients have had MRI’ results without any pathological features. Thus, MRI signs of carried out infection processes in central nervous system and inflammation in sinuses and throat were founded in 45 (75%) of autistic patients. It means the presence of chronic inflammation in the structures anatomically connected with the brain. It may have the function of trigger factor in etiology and pathogenesis of autistic disorders