In this study, a numerical model was presented to investigate the mass transport in a PEM fuel cell with partial blocks inserted in the gas channel designed to progress reactant gas distribution in the gas diffusion layer. The effect of the partial blocks design, the gas diffusion layer porosity on the reactant gas transport and distribution were examined. In particular, the desirable gas channel design for enhancing the performance of the PEM fuel cell is determined by examining the tilt angle of partial blocks. The results attained show that partial blocks introduced in the gas channel improve the PEM fuel cell performance. To validate the numerical model, an experimental test bench has been used to examine the cell performance. The simulation results specify that the effect of tilt angle is critical to the PEM fuel cell performance especially to minimize concentration over-potential. (C) 2014 Elsevier Ltd. All rights reserved.