The effects of periodic temperature perturbations at the inlet of a packed-bed catalytic reactor were investigated for a system of non-uniform catalyst activity that could arise through catalyst deactivation. A simplified model consisting of zones of active catalyst and inert packing of similar thermal properties was assumed. Simulations showed that large amplification, expressed as gain, can occur. The largest gain is observed at a resonance frequency. Both gain and resonance frequency depend on the number of layers of active catalyst and inert packing, the depth of the inert packing and catalyst layers.