The effects of gas diffusion layer's (GDL's) anisotropic bending stiffness on the degradation behavior of polymer electrolyte membrane fuel cells have been investigated under freezing conditions. We have prepared GDL sheet samples such that the higher stiffness direction of GDL roll is aligned with the major flow field direction of a metallic bipolar plate at angles of 0 degrees (parallel: '0 degrees GDL') and 90 degrees (perpendicular: '90 degrees GDL'). The I-V performances before and after 1000 temperature cycles between -10 and 1 degrees C of 90 degrees GDL stack are higher than those of 0 degrees GDL stack, and the voltages of 90 degrees GDL stack are decreased slower than those of 0 degrees GDL stack, indicating a higher durability of 90 degrees GDL stack. Furthermore, the values and increasing rates of high-frequency resistance of 90 degrees GDL stack are lower than those of 0 degrees GDL stack. However, the H(2) and air pressure differences before and after 1000 temperature cycles of 90 degrees GDL stack are very similar to those of 0 degrees GDL stack. The surface of anode catalyst layer (CL) of membrane-electrode assembly (MEA) with catalyst-coated membrane type in 0 degrees GDL stack appears to be more severely damaged than that in 90 degrees GDL stack, especially under the channels, whereas the surfaces of cathode CLs of MEAs in both 0 degrees and 90 degrees GDL stacks are slightly damaged after 1000 temperature cycles. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.