This paper presents a Measurement System of Cathodic Currents for copper electrorefining processes using Multicircuital Technology with Optibar intercell bars. The proposed system is based on current estimation using 55 magnetic field sensors per inter-cell bar. Current values are sampled and stored each 5 minutes for 7 days in a compatible SQL database. The method does not affect the normal operation of the process and does not require any structural modifications. The system was implemented in a electrorefinary site for on line measurement of 40 cells involving 2,090 sensors. © 2009 IEEE.