This paper presents a model integrating computational fluid dynamics (CFD) with electrochemical kinetics for predicting the performance of laminar flow-based fuel cell (LFFC). In the modeling analysis, we study the effect of parasitic current caused by the mixing of fuel and oxidant under critical operating conditions, which are between the ideal conditions without any crossover effect and the cell failure conditions due to too serious parasitic effects. The results show that the parasitic effect would cause a significant deviation of the cell performance compared with the ideal process when the LFFC is working under various critical conditions. The results also indicate that the parasitic current is an important factor for designing an efficient LFFC with high fuel utilization and high power density. (C) 2011 Elsevier Ltd. All rights reserved.