In recent years there has been an increasing interest in cation conducting materials, as these are one of the promising concepts for polymer electrolyte fuel cells (PEFC). In ongoing fuel cell research these materials are used either as a membrane or as a 5 wt.% solution in a mixture of lower aliphatic alcohols. As part of the fuel cell research at the DLR, Nafion powder was prepared by grinding Nafion beads in a ball mill under nitrogen cooling. The influence of different grinding parameters and the cationic group of the polymer on the resulting powder was examined.