This paper contends that over the life of the World Heritage Convention, the use of authenticity has not been well understood as a qualifying condition for inscription; that introduction of the complementary integrity requirement has simply compounded confusion; that the ideas which lie behind the two concepts are however critically important for managing nominations to the World Heritage List and improving conservation activity on World Heritage properties; and finally that use of the concepts need to be restructured to improve their effective application for the benefit of World Heritage properties. The paper contends that the key to restructuring use of the concepts is first recognizing the critical conceptual distinction between authenticity and integrity in measuring and designing strategies for improving the state of conservation of World Heritage properties, namely that authenticity may be understood as the ability of a property to convey its significance over time, and integrity understood as the ability of a property to secure or sustain its significance over time. The paper shows how the restructuring of the two concepts, defined in this way, can provide tangible indicators for applying the unified concepts in a number of contexts. Finally, the paper extends this approach and proposes an illustrative framework which could be explored for application to a range of heritage typologies found on the World Heritage List (archaeological sites, historic towns, architectural monuments and complexes and cultural landscapes).