The present invention relates to a membrane electrode assembly comprising at least two electrochemically active electrodes separated by at least one polymer electrolyte membrane, the aforementioned polymer electrolyte membrane having fibrous reinforcing elements which at least partly penetrate the polymer electrolyte membrane, wherein at least some of the fibrous reinforcing elements have functional groups which have a covalent chemical bond between the fibers and the polymer of the polymer electrolyte membrane.The membrane electrode assembly is suitable for applications in fuel cells, especially in high-temperature polymer electrolyte fuel cells.