BACKGROUND: During transition from children's to adults' healthcare, young adults with long-term conditions may show delays in psychosocial development compared to their peers without long-term conditions, and deterioration of their conditions' medical control. METHODS: This paper integrates the findings, already published in 10 separate papers, of a 5-year transition research programme. IMPLICATIONS: There is an important role for funders (commissioners) of adults' services to fund transitional healthcare, in addition to funders of children's services who currently take responsibility.It is important that healthcare provider organisations adopt an organisation-wide approach to implementation to ensure that good practice is adopted in children's and adults' services, not just adopted by enthusiasts in some specialties. This includes provision of 'developmentally appropriate healthcare' which recognises the changing biopsychosocial developmental needs of young people.Three features of transitional healthcare were associated with improved outcomes: appropriate parent involvement, promotion of young people's confidence in managing their health and meeting the adult team before transfer. These should be maintained or introduced as a priority.Child and adult healthcare providers should routinely explore with a young person how they approach transition and personalise their clinical approach thereafter.These implications are relevant for a range of stakeholders, including funders of transitional healthcare, organisations providing transitional healthcare and clinical practitioners.