Introduction. Cerebral palsy (CP) has a significant prevalence in industrialized countries and is characterized by a high level of disability. Children and adolescents with CP face challenging situations. Physical defects repeatedly manifest in the daily life of a child in the form of other extraordinary events such as hospitalization, surgery, prolonged immobilization, and separation from family. Such events can be accompanied by feelings of fear, anxiety, helplessness, and pronounced symptoms of maladjustment. Under these conditions, certain biological and social compensatory manifestations help to identify such complicated conditions and restore the normal functioning of the body. Compensatory manifestations are a type of compensatory defense mechanisms. The major role in establishing a system of protection is played by the relationship between a child and his or her parents. Defense mechanisms can be formed during the process of assimilation of protective parental behavior, or because of the inappropriate attitude of mothers to the child’s illness. The purpose of the research was to study the defense mechanisms in children with CP in the context of mothers’ relationship to her child’s illness. Materials and methods. The research involved 120 people. The experimental group included 30 children with CP aged 5 to 11 years and their mothers. The control group consisted of relatively healthy children (30) and their mothers. The following was used to achieve the goal: the elements of clinical and biographical method, projective technique, the technique of diagnostics of attitude to the child’s illness. Results and discussion. The repertoire of psychological defense mechanisms in children with CP is limited in comparison with those in healthy children. Children with CP are dominated by the defense mechanism of “denial” that can play a negative role in the process of adaptation of these children in a situation involving complex treatments. The mothers of children with CP share an emotionally intense relationship with their child’s disease. Excessively disturbing attitudes of the mother to the disease of her child can contribute to the formation of negative psychological defense mechanisms of negation type in the child, which reduces the child’s psychological compensatory capacity and capability of adaptation in conditions of complex treatment.