Managing the multiple demands of a chronic condition whilst negotiating the developmental tasks of adolescence and young adulthood is a process that is neither well described nor understood, particularly in relation to providing developmentally appropriate health care for young people. The importance of this issue is starting to be reflected within the literature, and although research into models of service delivery is emerging, a lack of user involvement in service development is apparent. This qualitative, user involvement study aimed to describe and understand the considered opinions of 19 young adults with diabetes who were receiving secondary care services about the provision of diabetes services for young people. The findings, gathered using semistructured interview and focus group methods, have potentially wide-reaching implications across primary and secondary health care, and across agencies providing services to children and young people, in terms of facilitating a person's transition through adolescence and into young adult life. Participants suggested key issues to address when developing services for young people, including staff consistency, civility, clinic structures which help a person navigate the health care system, provision of age-specific information, and support in relation to a range of health, emotional, social and developmental needs. Health care professionals can help young people to meet the expectations upon them as autonomous service users by modelling appropriate relationships, helping them to acquire skills and knowledge, and overcome barriers to them becoming active participants in their health care and achieving social participation in a fuller sense. It is somewhat arbitrary to delineate between adolescence and young adulthood in terms of age alone, but in this paper, 'adolescence' refers to the period between 11 and 15 years of age, and 'young adulthood' between 16 and 25 years of age. The phrase 'young people' will also be used to refer to people between 11 and 25 years.