Digitalisation is a real innovating project that has an impact on organizational structure of National Statistical Institute in terms of support services and statistic production competencies, results and impact and should bring clear benefit to the core process as: efficiency, speed, new capacity in customer service and stakeholder satisfaction. This work is based on a qualitative case study methodology focused on Italian Statistical Institute (ISTAT) which defines a programme for digital transformation and implements a digital platform to support documental flows. In 2016 the ISTAT identified digitalization as one of the seven strategical objectives that participate in the realization of modernization programme.The on going digital transformation process represents a real revolution on the organizational plan and has two priorities: the strengthening of administrative capacity and data and process digitalization. Concerning the operating plan the digital transformation programme is based on digitalisation of documents, processes and data streams. This complex programme is benefiting of the use of the Portfolio management transformation methodology from the very beginning of the planning phase. This model was implemented through the following phases: (1) the translation of the strategies into iniziatives; (2) the identification of the projects and activities; (3) the prioritizing, the evaluating and balancing of the portfolio. The first result achieved was the implementation of the digital documentary systems. The system is unique for the whole Istat, and all personnel, managers and not, are authorized and able to use it. The system integrates different components (official digital documents register - start up in July 2016; integrated certified emails-start up in March 2017, workflows and electronic signature- start up on 1st January 2018; digital preservation - start up in January 2018). During 2018 further IT capabilities have been included in the digital documentary systems. This first result has contributed to the implementation of a single documentary database. It allows to overcome the old usage of private silos of the different organizational structures, and to allow the sedimentation of the current documents archive of the Institute that is part of the documentary and archivistic heritage of the State Archives system. One of the results of the project was the promotion of several initiatives to implement the documentary workflow digitalization also related to the production processes and statistic dissemination that allows the integration with the overarching processes. An important step in the digitalization process is represented by the integration of the IT component for the massive certified emails within the digital documentary system. A further impact of the project is the implementation of redesign phase and simplification in digital key of administrative procedures and services not existing before, in accordance with privacy rules and full technological security. Main lessons learned on different plans: clear objectives, output definition, change management, team management, project leader role; organisational culture.