Opsoclonus-myoclonus syndrome (OMS) is a rare neurological disorder with unknown etiology and pathogenesis. There is not enough knowledge about psychological development of children with OMS. Objective. To study an influence of the time of disease onset and children’s age and type of disease course on psychological development of children with OMS. Material and methods. The study included 26 children with OMS of age between 1 year 7 months and 13 years, 10 boys and 16 girls. The following methods were used: analysis of patient’s development records, psychological interview with parents, assessment of emotional, behavioral, motion state and interpersonal relations. Results and conclusion. The disease onset at the early stage of ontogenesis (before 3 years) results into severe psychological disorders. Patients at the age between 3 and 5 years demonstrate the maximal number of developmental delays with possibilities of compensation. The article discusses a possible role of psychotraumatic and psychosocial factors in psychological disorders in children with OMS. The influence of age should be taken into account in planning of treatment and rehabilitation and evaluation of disease prognosis.