We demonstrate that the performance of a high-temperature polymer electrolyte fuel cell with a phosphoric acid-based electrolyte is almost independent of the way of introducing the acid into the membrane electrode assembly (MEA). The same power densities were obtained with different MEAs in which the poly(2,5-benzimidazole) membrane was either pre-doped or not and in which either one or two catalyst layers were impregnated with H(3)PO(4) Chemical analysis after shut down revealed that in all these MEAs the phosphoric acid distribution between the membrane and the electrodes was nearly the same. An MEA with acid impregnation via the electrodes was started up rapidly from room temperature, delivered a power density of 120 mW cm(-2) at 600 mV (H(2)/air, 160 degrees C, ambient pressure) after only 11 min and was operated for 1000 h (degradation rate. 0.06 mV/h) Based on the analysis of the H(3)PO(4) content in the MEA components, reflections on the kinetics of the redistribution of phosphoric acid within the MEA are provided (C) 2009 Professor T. Nejat Veziroglu Published by Elsevier Ltd All rights reserved.