This paper describes how to design and implement a mechanism that helps to mitigate sensor attacks on industrial control systems. The proposed architecture is based on concepts from fault-tolerant control techniques. This short note explains how a Kalman filter can be used simultaneously with optimal disturbance decoupling observers to improve the performance of the mitigation mechanism for sensor attacks in cyber-physical control systems. Our proposal mitigates attacks by generating a signal that compensates the change provoked by the attacker, while at the same time reducing the number of false alarms. We demonstrate the effectiveness of our proposal using a three tanks control simulation.INDEX TERMS Cyber-physical control systems, industrial control systems, secure control, sensor attacks mitigation.LUIS F. CÓMBITA received the B.S. degree in electronics engineering from Universidad Distrital, Bogotá, Colombia, in 1992, and the M.S. degree in electrical engineering from the Universidad de los Andes, Bogotá, Colombia, in 2002, where he is currently pursuing the Ph.D. degree.He joined the Engineering Faculty, Universidad Distrital Francisco José de Caldas, Bogotá, as an Auxiliar Professor, in 1997, where he is currently an Assistant Professor. His current research interests include cyber-physical systems security, modelling and simulation of dynamical systems, and industrial control systems.