Presently it is difficult to use (or re-use) the extensive wealth of information stored in the Public Administration data bases, even though it is widely recognized that such information can be helpful to face a wide range of social needs and promote innovation and business opportunities. Current information systems of PA’s are based on monolithic architecture models that include all the application software levels (silos). This approach does not ensure any flexibility when new needs rise; in particular when the existing applications could be converted into basic services to mash up information, implementing new different applications. The Open-DAI project deals with the following main issues: the opening of the huge amount of data stored in PA databases to the wide audience of potential users; the evolution toward an open architecture model for the PA information systems in order to overcome the monolithic and closed architecture models (silos); to facilitate software maintenance of existing silos, enabling PA to pace the evolution of legacy systems with Open Data initiatives. The Open-DAI project aims to address the problems outlined above by testing the efficiency and added value of a SOA and Cloud-based architecture on several PA by: • Implementing a data virtualization infrastructure deployed into a high availability infrastructure • Simplifying access to legacy vertical applications data, by providing a virtualized version of the data bases in the Cloud • Providing a new SOA data access layer, that could be combined in an appropriate manner in order to improve the products and services • Implementing the PA “open data” data hub, exposing it by using classic web services as well as other standard protocols. Assessing the business benefits for both PA and private organizations by developing new third-party added value services, focused on the following topics: transport and mobility, localization and geographic information, environment and pollution.