An experimental method and data analysis procedure are introduced to determine the liquid residence time distribution (RTD) of monoliths based on the imperfect pulse injection of a dye tracer. Repeatable experiments for two different lengths allowed for the deconvolution of the RTD function of a 375-mm-long monolith section with 3.64-mm(2) channels out of dense ceramic material. The experimentally determined liquid saturations are in fair agreement with the predictions of computational fluid dynamics (CFD) calculations, assuming uniform corner flow in the square channels. The laminar film flow results in strong tailing of the RTD curves and large reduced standard deviation values. Despite the reasonable agreement for the mean residence time the CFD model based on uniform liquid distribution over the monolith channels and the individual channel corners failed to describe the experimentally determined reduced RTD curves. Applying a measured corner-scale liquid distribution pattern in combination with the CFD model resulted in good agreement with the experiments. Furthermore, this approach also improved the agreement between measurement and model for the mean residence time. (C) 2004 American Institute of Chemical Engineers.