The high cost of the membrane materials of the currently favored perfluorinated sulfonic acid membranes, such as the Nafion and Dow membranes, is one of the primary obstacles for commercialization of the polymer electrolyte fuel cells. Radiation-grafted, partially fluorinated polymer membranes are considerably less expensive. Three Raipore membranes, R-1010, R-4010, and R-5010M were tested directly in 5 cm(2) H-2/O-2 fuel cells and examined by Fourier transform infrared spectroscopy. Under mild conditions, very good polarization results were obtained for cells with R-1010 and R-4010 membranes, compared with Nafion 117 membranes using Nafion-impregnated Pt/C electrodes and with electrode/membrane assemblies properly hot-pressed. Membrane degradation was observed from infrared measurements after cell operation, but both R-4010 and R-1010 membranes survived long-term stability tests of similar to 1000 h cell operation with reasonably good performance. Further work on both evaluation and modification of the membranes is still required.