A catalytic plate reactor consisting of closely spaced catalytically coated plates, where endothermic and exothermic reactions take place in alternate channels is studied. The influence of several design parameters on its thermal behaviour and performance is investigated by parametric sensitivity analysis using a two-dimensional reactor model. Parameters considered are: channel size; wall thickness and thermal conductivity; inlet temperature, composition and velocities; and kinetic parameters. It is demonstrated that different catalysts can show similar thermal behaviour and performance but exhibit different sensitivity behaviour. For the system investigated the strongest influence on reactor sensitivity comes from the activation energies of both exothermic and endothermic reactions.