The catalytic combustion of CH4/air in monoliths has been simulated through a commercial numerical fluid dynamic code. The program has been suitably modified in order to describe the heterogeneous reaction at the channel walls. Different flow arrangements have been studied in an attempt to closely match an experimental investigation reported in the literature. Single step overall rate equation has been used and identification of suitable kinetic constants performed through the use of optimization techniques. A framework for kinetic investigation accounting for complex Row structure and interaction with the chemistry is suggested. The relevant and sometimes overwhelming role of transport phenomena is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.