The influence of the permeation regime on the performance of catalytic membranes used for methane combustion has been investigated. To this end, membranes with different loadings of the active phase (Fe2O3) and different Knudsen contributions to the permeation flux have been prepared and used in combustion. A clear correlation has been found between the proportion of flux in the Knudsen diffusion regime and the light-off temperature for the membranes tested. (C) 2003 Elsevier Inc. All rights reserved.