An original set-up derived from the now standard hydrogen pump set-up is presented. The system enables isolation of the electro-osmosis as the lone macroscopic mass transport phenomenon, by minimizing or suppressing other external gradients, keeping the total pressure as the unique adjustment macroscopic parameter. The Electro-Osmotic Drag (EOD) coefficient was determined using 4 Nafion (TM) MEA (XL, 115, 117, 1110) as material, for temperature values in the 50-80 degrees C range, relative humidity (RH) values in the 30-90% range and current densities ranging from 1.2 up to 1000 mA cm(-2). Pure Nafion (TM) membranes exhibit the same behaviours with EOD coefficients between 0.8 and 1 and which do not depend on the current density or RH. Nafion (TM) XL based MEA show a singular behaviour with an EOD coefficient sometime as low as 0.4 and which depends on the RH. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.