A mathematical model describing the performance of photocatalytic reactors was proposed, and fitted using data for 4-chlorophenol degradation collected with a flat plate reactor. It was used to predict the performance of corrugated plate photocatalytic reactors, and this was then compared with subsequent experimental results. With only three experimentally determined parameters, the new model incorporates reaction kinetics, mass transfer, and photon transfer. The model-predicted performance of the corrugated plate reactors, with different structural parameters and under different hydrodynamic and illumination conditions, was found to agree with the experimental data reasonably well. (C) 2003 Elsevier Science Ltd. All rights reserved.