The influence of the anode bed geometry on the hydraulic behaviour of PEM fuel cells is assessed. Three basic geometrical patterns are studied, namely the interdigitated, the parallel and the serpentine ones, in their original, as well as in modified forms of them, in which their angles have been smoothed. Issues concerning the anode flow field of a fuel cell, the influence of the Reynolds number on pressure drop, the mass flowrate distribution along the anode bed channels and the residence time of the fluid inside the fuel cell are investigated. All different geometries are studied by means of 3D numerical flow simulations. The results indicate that the pressure drop, flowrate nonuniformity in bed channels and residence time increase as the flow Reynolds number increases. The effect of geometry smoothing on the results is also assessed. (C) 2016 Elsevier Ltd. All rights reserved.