In previous chapters, mechanisms of the deterioration of concrete and approaches to controlling or avoiding problems associated with deterioration have been examined. Although this is useful, it is hopefully evident that it is quite possible that a concrete structure will be threatened simultaneously by more than one type of deterioration mechanism. Moreover, the design of concrete does not solely revolve around durability – other characteristics will be required, such as compressive strength, to satisfy the structural and other functional requirements of a concrete element. The process of defining what characteristics concrete must have for a particular application is ‘specification’, and this chapter aims to examine the approach taken in specifying concrete and how the specification for durability fits into this process.