The relationship between through-plan polytetrafluoroethylene (PTFE) distribution on a gas diffusion layer (GDL) and unitized reversible fuel cell (URFC) performance was investigated. Titanium (Ti) - felt was used for the oxygen-side GDL and treated with 10wt.% PTFE dispersion to enhance hydrophobicity. The dependence of PTFE distribution on the PTFE drying conditions was examined using scanning electron microscopy (SEM)-based energy dispersive X-ray spectroscopy (EDS) imaging. The EDS image maps revealed that the PTFE distribution strongly depended on the drying condition of the PTFE; drying under atmospheric pressure yielded a highly non-uniform PTFE distribution in the through-plane direction, whereas drying under vacuum pressure yielded a relatively uniform PTFE distribution. The cell performance of URFCs was then evaluated based on measured current voltage characteristics during both electrolysis and fuel cell operation modes. Results verified that compared with non-uniform PTFE distribution, a uniform distribution in the Ti-felt GDL improved the fuel cell performance under the fully wet condition (relative humidity = 100%). By applying the Ti-felt GDL with uniform PTFE distribution in the through-plane direction, the current density at the cell voltage of 0.6 V was increased by a factor of about 1.9 compared with the Ti-felt with non-uniform PTFE distribution. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.