In this study, electrochemical removal of oxygen from seawater in industrial scale is demonstrated. A test rig with an industrial scale electrochemical cell has been constructed and tested with filtrated oxygen rich seawater. The electrochemical cell was comprised of a silver mesh cathode and an iridium oxide anode with a cation exchange membrane. The effects of flow rate, pressure, and applied voltage on oxygen removal efficiency and resulting current were studied. Also, the differential pressure between the anode and cathode chambers affected the performance of the cell, and an overpressure of 0.20-0.30 bar in the anode chamber was optimal in order to obtain maximum oxygen removal. It was possible to achieve an oxygen concentration lower than 5 ppb in seawater at a flow rate of 5 L min(-1). No scaling or biofilm problems were observed during a 200 h test period.