The structure and solvent (water, methanol, etc.) dynamics of a number of fuel membrane electrode assembly (MEA) samples are studied with nuclear magnetic resonance microimaging with spatial resolution of tens of micrometers. The micrometer-scale inhomogeneity of the samples is observed and confirmed with various weighting methods. In particular, diffusion coefficients at different positions in MEA are clearly differentiated. Furthermore, chemical shift selection imaging enables one to investigate the spatial distribution and dynamics of individual chemical groups. These types of information offer us insights into the working principle of fuel cell and pave the way to in situ studies of operating fuel cells. (C) 2009 Elsevier Inc. All rights reserved.