This paper presents the modeling, simulation and optimization of a single channel proton exchange membrane fuel cell (PEMFC) using computational fluid dynamics methods. The shape optimization of the flow-channels was employed to improve the electrical performance of the fuel cell. The maximization of the current density was the objective function of the single-objective optimization problem, the upper and lower widths of the flow channels were the control variables and a cross-section area restriction was imposed. The optimized flow-channel PEMFC presented improved current generation characteristics, showing higher current and power densities and a more uniform current density distribution than the rectangular flow-channel.Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP)FAPESP: 16/12397-0; 14/50279-4