Background. Stereotypical self-injurious behavior (SSB) in children with autism spectrum disorders (ASD) and other mental developmental disorders is considered a widespread and destructive form of behavior. SSB is heterogeneous both in the severity of clinical symptoms and in the causes (biological, psychogenic) of occurrence. SSB in patients with ASD occurs with high frequency and is associated with constant psychotraumatization due to a tendency to pathocharacterological reactions, more frequent hospitalizations in psychiatric institutions, as well as a number of negative social conditions that lead to a deterioration in the quality of life of patients and their relatives. Objective: to study stereotypical self-injurious behavior in patients with psychotic forms of autism spectrum disorders. Study Materials. Based on the Department of Child Psychiatry, a survey of patients (n=25): male (n=19) and female (n=6), aged from 3 years 4 months to 11 years 5 months (mean age 7 years) who were undergoing inpatient treatment in the clinic of the Federal State Budgetary Institution National Center for Children's Health from 2020 to 2023. Inclusion criteria: 1) meeting the ICD-10 diagnoses of childhood autism (ChA, F84.02), atypical autism with mental retardation (AA with mental retardation, F84.11), atypical autism without mental retardation (AA without MR, F84.12), 2) presence of psychotic symptoms during an attack. Non-inclusion criteria: 1) severe organic brain damage, including in patients with cerebral palsy, 2) hereditary diseases and genetic syndromes, 3) other forms of ASD, except for those indicated. Research Methods: clinical-psychopathological, psychometric, clinical-anamnestic, statistical. Results. The identified psychotic attacks had a different structure (with and without regression phenomena), the leading syndrome being catatonic. In patients with psychotic forms of ASD, SSB is most often part of stereotypic behavior and actions, and can have varying severity -from insignificant to traumatic. SSB is often combined with manifestations of a psychopath-like syndrome in the form of heteroaggression and disinhibition of drives; it occurs with a higher frequency in severe cases of the disease with an unfavorable prognosis. SSB is more often typical for children with severe speech underdevelopment. Stereotypes in psychotic forms of autism (F84.02, F84.11, F84.12 according to ICD-10) are heterogeneous in clinical manifestations and can be expressed by both simple and more complex repetitive actions, self-harming actions, actions close to rituals and one-sided interests.