This paper deals with the electrical resistivity monitoring of the Ketzin CO2 injection pilot (CO2ReMoVe EC project) through time-lapse CSEM measurements. There, 3 boreholes about 800 m deep have been especially designed for current injection at reservoir (sandstone) depth. CO2 is directly injected in a saline (∼240 g/l) aquifer. Prior modelling results indicated that the increase of electrical resistivity generated by the CO2 plume (gaseous and liquid CO2 phases) supposed to be highly resisitive, would generate measurable changes in the EM fields on the surface, when injecting current directly inside the reservoir. In order to highlight and follow these expected resistivity changes, 3 CSEM surveys were performed in August 2008 (baseline prior to injection), June 2009 and August 2010. Each time, 13 EM stations have been recorded during current injection of a square wave at 3 frequencies (0.125 Hz, 0.5 Hz and 4 Hz) in two configurations (“double mise à la masse” (2×MAM) and “mise à la masse–surface” (MAM-Surface)). This paper only presents results of the 2×MAM configuration at 0.5 Hz.