Many young people with childhood-onset diseases, including rheumatic diseases, continue to require medical care into adult life. There are many differences between paediatric and adult health care which can make this change a dramatic and difficult one for young people and their families. Transitional care services aim to equip young people with the appropriate knowledge and skills to cope with this change. This chapter will describe the differences between transition and transfer, and the different perspectives of those involved in the transition process, and will discuss the determinants of a successful transfer. Transition models currently used in practice will also be described, as will the evolving evidence base that is contributing to the further development of transitional care services.