AIMS To explore the experiences of young people and their carers during the transition from child to adult diabetes services. METHODS Longitudinal qualitative case studies of young people and carers undergoing transition in five different diabetes services in the UK. RESULTS When young people make the transition from child to adult diabetes services, it is assumed that they will also undergo a parallel transition away from dependence on parents to independent diabetes management. However, the lives of young people are characterized by interdependencies, which are facilitative of their diabetes management and which are not always reflected in healthcare policy and practice. This can lead to discontinuities of information and undermine mothers' ability to continue to support their child into young adulthood. Mothers also lose contact with the service at a time when they are undergoing developmental challenges of their own and need support in adjusting to a new existence. CONCLUSIONS There is a clear need to develop service structures that recognize the continuing role played by mothers in the diabetes care of young adults.