The fabrication and electrochemical performance of polymer electrolyte fuel cells based on a carbon-filled gas diffusion layer (CFGDL) were studied in detail. The CFGDL consists of a PE-704 carbon electrode backing filled with a mixture of carbon powder and PTFE. The results obtained from the performance evaluation and cyclic voltammetry (CV) analyses indicate that the loading of the carbon powder in the CFGDL plays a critical role in the performance of the fuel cell and utilization of Pt, but the presence of PTFE in the CFGDL has less influence. The carbon content in the CFGDL not only affects the area specific resistance of the CFGDL but also affects the Pt utilization of the catalyst layer, the total cell resistance and thus the cell performance. The optimal performance of the PEFC was obtained when the CFGDL was filled with carbon to 6 mg cm(-2) and PTFE of 40%. The relationship between the surface morphology and microstructure of the CFGDL and the electrocatalytic activity of the cell is also discussed. (c) 2005 Elsevier B.V. All fights reserved.