Many children and young people now survive into adult life with complex conditions that previously would have been lethal in infancy. These conditions often affect many bodily systems and many aspects of their lives. Poorly planned transition from young people’s to adult-oriented health services can be associated with increased risk of non-adherence to treatment and loss to follow-up, which can have serious consequences. There are measurable adverse consequences in terms of morbidity and mortality as well as in social and educational outcomes. Well planned transition improves clinical, educational and social outcomes for young people.