A channel is a significant part of a proton exchange membrane fuel cell (PEMFC), and the configuration of the channel has a great effect on the mass transfer of the PEMFC, which directly influences the performance. In this study, a three-dimensional, single-phase, and non-isothermal model of a PEMFC with a single straight channel is developed. Based on the model, genetic algorithm (GA) is adopted to obtain an optimal design of the channel configuration. Power consumption of flow and output power of a PEMFC are considered into the objective function, and the width of bottom and top edges of the channel, in both the anode and cathode sides, are selected as variables. The optimal design obtained is a trapezoidal channel. At an operating potential of 0.4 V, the increment in current density in the optimal design is 10.92% compared to a basic design having a square channel. Moreover, the optimal design shows more uniform distributions of reactants and current density than the basic design. (C) 2016 Elsevier Ltd. All rights reserved.