BACKGROUND: As the incidence of Type 1 diabetes mellitus has increased during childhood, more patients will experience the transfer from paediatric diabetes care to adult diabetes care. In order to achieve a coherent care system it is essential to identify conditions, events and actions that hinder and facilitate a successful transition between these settings. OBJECTIVES: The aim of this study was to describe care culture in paediatric and adult diabetes outpatient clinics and implications for care of adolescents in those settings. METHODS: Fifty-one participant observations and 10 semi-structured interviews with diabetes care providers were carried out in two paediatric clinics and two adult clinics in Sweden. Data were analysed simultaneously with data collection, using a constant comparative method developed in the grounded theory tradition. RESULTS: In the analysis process, one core category, four categories and subcategories were generated. The core category shifting aspects of diabetes care culture is related to the categories. The categories support of self-management and unfocused behaviour describes mostly similar strategies and attitudes in paediatric and adult diabetes care, while multidimensional support and decreasing visibility describes differences in characteristics of care culture in paediatric versus adult diabetes care. CONCLUSIONS: The decreased visibility might have consequences for vulnerable patients, such as those with insufficient metabolic control and self-management abilities. By illuminating shifting aspects of care culture, care providers can be given a basis for reflection and discussion of how the care is provided in their own setting and how different environmental conditions and care strategies can promote formal and informal contacts between patients and care providers.