The cooling system of a 2 kW air-forced open-cathode PEM fuel cell stack has been designed based on the prediction of the air flow calculated by means of a theoretical model that includes both the electrochemical behavior, and the heat and mass transfer processes as a function of the power output. The influence of the cathode channel geometry on the heat management has also been considered, specifically on the total pressure drop imposed to the air fan system. These results have been used in the design of a dynamic and optimum cooling system, based on compact axial fans, that has included the number of components, their location and its working conditions as a function of the instantaneous current intensity generated by the PEMFC. To asses the performance of the cooling system, stack surface temperature profiles have been measured using infrared thermographic images. Results obtained confirm the correct performance of the fan system, providing a cooling air rate that perfectly adapts to the variations in the power generated by the stack. Additionally, the stack operation has been evaluated and characterized determining the polarization curves. Copyright (c) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.