The deterioration of rubber composites filled with different types of fillers was analyzed to determine the influence of cyclic high-pressure hydrogen exposure. The mechanical properties of acrylonitrile butadiene rubber (NBR) unfilled and filled with carbon black or silica were evaluated. The storage modulus of the silica-filled NBR decreased in the rubbery state as the number of exposures increased, while those of the unfilled and carbon blackfilled NBR did not change. Changes in the chemical structure such as hydrogenation or chain scission were not detected in the solid state NMR spectra of the exposed composites. However, deterioration of the filler-gel structure formed at the interface of the filler and polymer was observed in the silica-filled NBR. Fracture of this filler-gel structure occurred due to fatigue in the silica-filled NBR resulting from a reduction of the elastic storage modulus caused by cyclic high-pressure hydrogen exposure. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.