In order to investigate the effect of operation temperature on the liquid water removal in the polymer electrolyte fuel cell, a one-dimensional steady state mathematical model was developed for the cathode gas diffusion layer (GDL). Numerical results indicate that liquid water saturation significantly increases with increases in the operating temperature of the fuel cell because the capillary pressure in the hydrophobic GDL decreases with increasing temperature. An elevated operating temperature has an undesirable influence on the removal of liquid water inside the GDL. A reported peculiar phenomenon in which the flooding of the fuel cell under a high operating temperature and an over-saturated environment is more serious in a GDL combined with a micro-porous layer (MPL) than in a GDL without an MPL (Lim and Wang, Electrochimica Acta, 49, pp. 4149–4156, 2004) is explained based on the present analysis.