Carbon black-filled EPDM were investigated by means of 129Xenon NMR spectroscopy. Unvulcanized elastomer EPDM was filled with 3 types of com. available carbon blacks, differing in particle size and sp. surface. 129Xe NMR spectra indicate that Xe atoms are absorbed in the mobile EPDM domains of both filled and unfilled material. In addn., a resonance of Xe adsorbed in the bound rubber fraction was detected. From the chem. shift and line width of this resonance the authors conclude that the EPDM chains around the carbon black particles have a strongly diminished mobility.