Cochlear implant is a revolutionary neural prosthesis that restores hearing in deaf people. Electrical impedance measurement of the cochlear implant electrode using the telemetry feature of the circuit provides information about the integrity of the electrode. The aim of this study was to observe changes in electrodes’ impedance after 10 to 12 years of device usage. The study enrolled children who underwent cochlear implantation with Nucleus devices, between February 2006 and September 2008. In all cases, impedances increased from the intraoperative to the initial fitting session, then decreased after the first fitting session and had different behaviours over long time of devices’ use. In only 8 out of 20 cases (40%) electrical impedance values did not change over 10 years of implant use. Periodic impedance telemetry measurements after implant activation are important for monitoring the integrity of the electrodes and for modifying stimulation parameters that may help preserve auditory performance.