The article covers the issues of family functioning as one-child and multi-child families from the perspective of the children of these family systems. A family model of 2 + 1 is currently preferred while certain doubts are associated with families with many children in assuming that they often live at a lower level . Most frequently in one-child families the child is the centre of attention and occupies a privileged position. On the other hand to be the only child is associated with fewer interactions within the family, as well as a limitation of the amount of roles in the family. Parents usually are excessively focused on their child, overly protect him and have too high expectations of him. More often in these families there is emphasis on stimulating the child in the intellectual sphere. In the case of large families a lot depends on how the family consciously and responsibly decide about the family interractions. Children functioning in large families more often can adapt to the changing conditions of life, they are able to face various difficulties and have more experience in establishing relationships with others. The aim of our research was to determine how the children from single-child and multi-child families, assess the situation in the family. It analyzed the relationships in families, depending on the number of offspring, what is the level of consistency in the relationship ties between individual family members and the level of adaptability, namely the ability to make changes in the family. A questionnaire of our own design was used at the study, Family Adaptability and Cohesion Scales and Parent-Adolescent Communication Scales D.H. Olson and associates. The situation in the family has been evaluated by 120 grammar school students, including 60 who were the only child and 60 people from large families. Studies have shown that in many aspects, both families with one child and multi-child families are functioning properly. However, it is necessary, to provide financial support for big families to assure the children get an equal start.