Most designers of Polymer Electrolyte Fuel Cells (PEFCs) supply the PEFC with humidified gas to prevent its membrane from drying. Because the steam generated by the electrochemical reaction is added to a humidified supply gas, the steam partial pressure in the cathode channel forces a supersaturated state. Therefore, the PEFC has water management issues, such as flooding and Plugging. Many researchers have studied these issues in the cathode side Using a Visualization technique, and have introduced water repellency processing to the gas channel and GDL (gas diffusion layer) as a solution. However, the flooding/plugging phenomena in the cathode do not occur alone, and are influenced by the flooding/plugging phenomena in the anode channel through the membrane. Moreover, the water transport phenomenon through the membrane is affected by the locations of the flooding/plugging phenomena in each gas channel. Therefore, we aim to examine the water transport phenomenon through the membrane by the two-pole simultaneous image measurement, and to propose all Optimum water management method. This work shows that the flooding/plugging phenomena on the anode side are clearly related to water transportation from the cathode side through the membrane. (C) 2009 Elsevier B.V. All rights reserved.