This work shows a theoretical analysis of primary and secondary current distributions along a boron-doped diamond (BDD) anode of a filter-press-type FM01-LC reactor. Hydroxyl radical formation via water discharge was used as a test system. Microelectrolysis studies confirm that hydroxyl radicals are formed at potentials between 2.3 V <= E <= 2.75 V vs. SHE and that at higher potentials oxygen evolution reaction (OER) occurs. Primary current distribution is more uniform away from the curved corners of the cell, originated by the spacer between electrodes; however, the current distribution values at the corners and near to them, differ with a magnitude order of 1 x 10(-5); hence, primary current distribution at BDD anode in the FM01-LC reactor can be considered uniform. Secondary current distribution at different over potential values of 1.7, 1.9 and 2.15 V, respectively, did not show border effects. Attenuation of secondary current distribution is associated to kinetic parameters of water discharge on BDD and appropriate cell design. The importance of secondary current distribution for the production of hydroxyl radicals on BDD anode, to avoid OER, is discussed. (C) 2013 Elsevier B.V. All rights reserved.