The authors of the paper consider the problem of social formation of senior preschool children with moderate intellectual development disorders as a precondition of studying at school. The problem is solved in the aspect of general favoring social development of this category of children, namely formation of soft-skills in preschool children with intellectual development disorders. The theoretical-analytical work of studying the problem of formation of the social readiness of senior preschool children with moderate intellectual development disorders was based on the diagnostics of the social readiness to studying at school of this category of children and two components in its structure (communicative and social competences), which content includes criteria (cognitive-motivational; behavioral; cognitive; operational), indicators and their levels were determined. The formation of the social readiness of children with moderate intellectual development disorders to studying at school was investigated competence by competence (social and communicative competences), taking into account the comparative principle by juxtaposing their results with ones of children with light intellectual development disorders. There was empirically revealed the low formation level of the social readiness of senior preschool children with moderate intellectual development disorders that is conditioned by an insufficient formation level of its structural components: social – at the expanse of low indicators of understanding him/herself as a member of a social group by a child, non-formation of the ability to perceive and produce information about him/herself, own inclinations, significant adults, inability to observe social norms and values in behavior and interaction with others, rigidity of behavioral strategies at interaction with others, non-conformity of reaction to their words and actions, non-formation of the ability to listen, not to interrupt; communicative – because of difficulties to understand addressed speaking, inability to enter the communication process, non-formation of knowledge about communication culture rules in relation with coevals and adults, absence of self-control/mutual control in communication situations, non-formation of the ability to correlate verbal communication means with nonverbal ones.