The objective of this paper is to study hydrogen assisted catalytic combustion of methane on platinum experimentally and numerically. In the experiment, we measure the exit temperatures of methane/hydrogen/air mixtures flowing at atmospheric pressure through platinum coated honeycomb channels. A single channel of this monolith is investigated numerically by a two-dimensional Navier-Stokes simulation including an elementary-step surface reaction mechanism. Furthermore, a one-dimensional time-dependent simulation of a stagnation flow configuration is performed to elucidate the elementary processes occurring during catalytic ignition in the mixtures studied. The dependence of the hydrogen assisted light-off of methane on hydrogen and on methane concentrations is discussed. The light-off is primarily determined by the catalyst temperature that is a result of the heat release due to catalytic hydrogen oxidation. Increasing hydrogen addition ensures light-off, decreasing hydrogen addition requires an increasing methane feed for light-off. (C) 2000 Elsevier Science B.V. All rights reserved.