Recent progress is reported in preparing membrane/electrode assemblies for polymer electrolyte fuel cells based on radiation-grafted FEP-g-poly(styrenesulfonic acid) membranes. MEAs with an improved interface between the membrane and commercially available gas diffusion electrodes were obtained by Nafion((R))-coating of the membrane and hot-pressing. These improved MEAs showed both, performance data comparable to those of MEAs based on Nafion((R)) 112 and an operation lifetime in H-2/O-2 fuel cells of more than 2000 h at 60 degreesC and 500 mA cm(-2) current density.