The aim of this thesis is to identify the factors which can cause social exclusion of prechool children and the possibility of implementing prevention. Case study method was conducted in this research. A six-year-old child's developmental status and forms of behaviour were observed during one school year. In order to collect data, the methods which were used included participant observation, taking notes, pedagogical documentation of educators and the professional team, photo and video recordings of the child while in activities, and semistructured interviews with children from the group to which the observed child belongs. Factors and unfavorable life circumstances that significantly influenced the child's developmental status were analyzed. The results of the research indicate a correlation between unfavorable life circumstances, an insufficiently stimulating family environment and the absence of adequate support in meeting the child's developmental needs with an extremely high risk of social exclusion. Exposure of a child of early and preschool age to the risks of social exclusion can have serious consequences on his development, primarily the development of all his potentials and his development as a person, which therefore greatly affects his future. His integration into society and academic success may be jeopardized if his family and system do not provide him with adequate support. The family, the environment in which the child acquires the first notion of security, sometimes under the influence of various factors cannot ensure that all his needs are met. In these circumstances, the community should take responsibility for the future development of the child. In order to ensure optimal support, formalized cooperation and networking between educational, social and health systems are necessary. The support should be systematically organized, applicable with specific activities, legally monitored and periodically evaluated.