In this study, wet-laying process, mostly used in pulp and paper industry, was employed for the fabrication of composite gas diffusion layers (GDLs) for polymer electrolyte membrane (PEM) fuel cells. Cellulose fiber-based composite GDL was manufactured without using polluting, volatile organic compounds so that a green and environmentally friendly process was utilized. Fabricated cellulose-based composite GDLs were characterized ex situ by resistivity, mechanical strength, and porosity measurements and investigation of their morphology by SEM. Carbon-cellulose fiber-based electrically conducting composite GDLs with excellent flexibility, uniformity, and porosity were achieved. Gas diffusion electrodes were prepared using electrospraying technique to provide high surface area and homogenous dispersion. Moreover, PEM fuel cell performance of the fabricated composite GDLs was investigated for the first time in literature.