The performances of multi-scale networks are investigated considering the selectivity of consecutive catalytic reactions occurring at the coated walls of the parallel microchannels. The impact of the channel arrangement on the global performance of the network is analysed. It is shown that controlling the flow uniformity through the parallel channels can result in the improvement of the overall reaction selectivity, while reducing simultaneously the overall pressure drop through the network. The robustness of such networks is also analysed through a channel clogging simulation. (C) 2009 Elsevier Ltd. All rights reserved.