The dissertation “Environments for the Development of Health Competence of Children With Diabetes Mellitus�, aims to reveal not only the complexity of health competence development in children with diabetes mellitus (how development is carried out, who organises educational environments), but also what health competence components are important in type 1 diabetes. The following dissertation focuses on the environment for the development of health competence of children with diabetes mellitus. In accordance with theoretical and empirical research, non-formal environments for the development of health competence were identified, their organisation was discussed, health educators as well as the applied educational activities and methods were described. On the basis of knowledge gained during dissertation research, it will be possible to model the development of health competence in different environments and contribute to the implementation of secondary prevention as well as to the improvement of the quality of life of children with type 1 diabetes.