In a previous paper an electrochemical method for the removal of dissolved oxygen from water was described. In that work the oxygen-rich water was passed through a three-dimensional cathode and the dissolved oxygen was reduced on the cathode surface to water. In the present study electrochemical oxygen removal and, especially, the scale-up of the deoxygenation cell were investigated. The volume of the three-dimensional cathode was enlarged and suitable cathode materials and membranes were tested. The maximum flow rate and the optimum cell voltage were determined. Finally, two cathodes were connected in parallel flow. A flow rate ten times higher than that of the former laboratory-scale cell was achieved. Over 99.95% of the dissolved oxygen was removed. No significant amount of byproducts, hydrogen or hydrogen peroxide, was observed.