The operation of a laminar flow fuel cell (LFFC) involves complex interplay between various mass and electrochemical transport processes. Hence, to better design and more accurately predict performance, we developed a fully-coupled 3D numerical model that includes all the transport processes and electrochemical phenomena. Specifically, the model is based on the equations for the mass, momentum, species, and charge balances along with Butler-Volmer equations for electrode kinetics. The developed model was in excellent agreement with experimental data on a micro laminar flow fuel cell (mu LFFC) with a bridge-shaped microchannel cross-section. Then, we used the model for a parametric study evaluating the influence of different operational and geometrical parameters (bridge aspect ratio, reactant flow rates, oxidant concentration) on the fuel cell performance (peak power density, fuel crossover, crossover current, power losses). The observed correlations were explained on the basis of mass and electrochemical transport phenomena, e.g., the behavior of the depletion zones at the fuel-oxidant and reactant-electrode interfaces. Based on these results, we recommend further design considerations for LFFCs. Although, the model was specifically developed for a particular mu LFFC configuration, the computational model can be used to design and predict behavior of a wide variety of LFFC configurations. (C) 2014 Elsevier B.V. All rights reserved.