Corrosion of reinforcement steel is on of the main durability issues for concrete structures, especially in costal areas and in countries where de-icing salt is regularly used. The SensCore system, dedicated to the monitoring of corrosion in reinforced concrete structures, is a wireless sensor network, designed to detect and predict the onset of steel corrosion in concrete. The system consists of sensors, dataloggers and a measurement hub that concentrates the data from several dataloggers and transmits it to a central database, where it can be accessed by the authorized users. The sensors are able to measure several parameters, which are critical to evaluate the present and future risk of rebar corrosion in concrete. In particular the corrosion current and the concrete humidity are measured at several depths between the concrete surface and the rebar depth, to analyze the progression of the corrosion front as well as evaluate the performance of hydrophobic coatings or waterp roof membranes. The sensors are extremely simple to deploy and can transmit their data wirelessly to the measurement hub, thus eliminating the need to install any wiring in the structure to be monitored. Because of its modular design, this system is adapted to structures of all sizes, from a small overpass to a long tunnel and can be installed in both new and existing structures. The SensCore system integrates seamlessly with other sensing technologies, based on electrical, vibrating wire or fiber optics. It is therefore possible to combine several technologies in order to implement an optimal monitoring network for a specific structure. The SensCore system has been deployed on tens of structures, including the I35 St. Antony Falls Bridge in Minneapolis, USA, the Gotthard street tunnel in Switzerland and the Colle Isarco Bridge in Italy. This paper presents the system architecture and several application examples.