Public pre-school educational establishments — crèches and kindergartens — if properly combined with family education provide for the most progressive form of educational influence in a socialist society, the social education of children. The transition from crèches to kindergartens often means a very considerable change of environment for the children, a change of requirements and living conditions, resulting from a lack of system in the educational purposes of the two pre-school establishments. It is therefore necessary to co-ordinate the educational care for children in the whole pre-school period very thoughtfully, to introduce a system into it and thus ensure the co-ordination of educational work between crèches and kindergartens so as to make the children’s passage from one establishment into the other as smooth as possible. In connection with this very important problem a research was organised involving 3-year old children entering the kindergarten. The purpose of this research was to find out how the children behave and react shortly after the passage from the cr6che to the kindergarten, how developed they are physically and mentally, how the change of environment affects them, how they mix with the other children in their group, to what extent they are self-sufficient, if they are able to fulfil the requirements of the kindergarten, if they meet with any objective difficulties, also in comparison with the children who have come to the kindergarten straight from the family environment without having been in crèches previously. Even though the research did not nearly cover all the important questions connected with the transition of 3-year-olds to kindergartens, it did provide some objective data for working out uniform programmes of educational work for children from 0 to 6 years of age as well as some measurable data about the possibilities of a smooth continuation of the educational work of the crèches by kindergartens. On the basis of the results of researches, verified by practical experience, and a theoretical elaboration of some problems outlined above, it will be possible to build up a really universal, harmonious educational system for children from 0 to 6 years of age.