Modeling cyber and physical interdependencies – Application in ICT and power grids Presently, there is a poor knowledge about the coupled systems and their interdependency. Failures caused by cascade effects are increasing and operators’ systems do not know how to control adequately the negative consequences on their systems. At the same time, critical infrastructures due to their relevance are potential targets of outlaw groups, ill- disposed people, and terrorist groups. The modeling of the coupled infrastructures may lead to an evaluation of the power system security and could help to asses the impact of the cascading effect between ICT and Power Grid. By consequence, it is possible to find vulnerabilities and relevant risk indices of the power system.In our research group, different ways of modeling critical infrastructures in their interdependencies are explored: a behavioral co-simulator, the use of Complex Networks theory and Bayesian Networks among others theories and tools which can be investigated. Because of the necessity to assess the security of the coupled infrastructures, which implies the modeling of theses networks, precedence graphs and modified FMECA are being employed for this purpose.