The RESIIST project proposes a methodology and tools for (a) data collection, (b) modelling, (c) decision support (d) simulation and visualization (e) help with the implementation of decisions to evaluate in time the resilience of critical infrastructures in order to define the possible strategies and to carry out analyses on original criteria. In order to supply goods and services to populations, various socio-technical changes allow us to draw the following conclusions: Statement 1: stakeholders’ needs evolve and tend to make these infrastructures more complex to manage and understand. They are pushed into their operating limits and suddenly become critical. Statement 2: Whatever is the type of these infrastructures (production system or territory), they are increasingly connected and interconnected which further contributes to their complexity. Statement 3: Various and numerous disruptive events can affect the proper functioning of these infrastructures are. Instability of such infrastructures becomes then the norm. This instability is exacerbated by influences and interactions between infrastructures and the territories on which they operate. Statement 4: The loss rate related to the occurrence of disturbances then impacts several dimensions (human, economic, ecological, technical ...) These statements highlight the role, relevance and importance of the resilience of these critical infrastructures for companies, communities and managers involved and concerned with managing the consequences of disturbances. This clearly demonstrates the need for a continuous resilience assessment approach. This is indeed requested to feed decision-making tools enabling these stakeholders to effectively manage their infrastructures and to limit the consequences of disturbances with regard to the different dimensions mentioned above. The RESIIST project makes the assumption that a certain number of heterogeneous data are relevant, available and then must be exploitable. It proposes in response to the previous observations: •A critical infrastructure modelling and resilience assessment approach based on six activities: (i) continuous collection of data issued from various sources, (ii) processing and analysis of these data to derive relevant information on multiple dimensions (human, social, financial, technical), (iii) development of a model of critical infrastructure that is as faithful as possible, under the form of a Digital Twin of the critical infrastructure, making it possible to structure, organize and facilitate access to data, information and knowledge, (iv) evaluation of resilience, (v) behavioural simulation of the model and visualization of results, (vi) decision-making and assistance to implementation of decisions; •The definition and use of resilience indicators for multi criteria decision support; •The development of tools supporting the modeling, evaluation and simulation process; •Smart visualization according to the need expressed by the stakeholders. RESIIST proposes then to manage, share and use heterogeneous and numerous data and models to assess the resilience of a critical infrastructure considering diverse analysis dimensions. As a result, resilience will be more fully estimated, and decision makers will be supported by using RESIIST deliverables to make the most relevant decisions based on multiple perspectives and criteria. On the scientific level, RESIIST is based on the problems concerning research, definition, formalization and validation of: •New indicators based on the available data and corresponding to Economic, Technical, Environmental, Regulatory, Social, or Human dimensions; •Procedures for interpreting and exploiting these indicators; •Potential occurrences of disturbances (causes and effects) modelling and analysis •Models of representation of critical infrastructures integrating these indicators to assess resilience; •Decision-making process support and follow-up of the implementation of the decisions.