Dismantled areas variety and size, both in Italy and abroad, for square measures and, very often, for physical and environmental quality, represent one of the main resources to start processes of territorial physical and functional reorganisation as well as economic development in the cities. This paper is part of a wider research whose purpose is building a tool supporting the expectation and decision phases of possible interventions on vacant sites from the public actor. In connection with that purpose, the goals are the following: – working out one single criterion of understanding the several examples of vacant sites in Italy and abroad; – determining the (territorial, social and economic) factors that successfully carry out the transformation of a vacant site; – analysing the tools and procedures helping manage and accomplish the interventions. In this place, we are carrying the results regarding the determination and different modalities for implementing the interventions.