This experimental study was undertaken to resolve the contrasting viewpoints on the role of a microporous layer (MPL), attached to carbon paper porous transport layer (PTL), on the net water transport in a polymer electrolyte membrane fuel cell (PEMFC). Experimental results on single cells with and without cathode MPL show no statistically significant change in the net drag coefficient that could be attributed to the presence of the MPL. In contrast to the two prevailing but contrasting viewpoints, our results indicate that the MPL on the cathode neither enhances back-diffusion nor increases water removal from the cathode catalyst layer to the PTL. (c) 2006 The Electrochemical Society.