In this work, the performance of proton exchange membrane (PEM) fuel cells has been analyzed for different oxidant (air and oxygen) flow rates (supplied at the cathode side). The performance analysis of a single PEM fuel cell coupled with a direct current (DC) permanent magnet motor (as load) was analyzed for air and oxygen. With an increase in the air flow rate, the maximum current values of the PEM fuel cell increase due to the reduction in the concentration of polarization losses (in the polarization curve) and the voltage regulation for the load increases. The maximum power production in a PEM fuel cell is a logarithmic function of different air flow rates. In this system, a DC permanent magnet motor with a reduction gear was used as a load on the PEM fuel cell. With the increase in air flow supply rates, the starting torque of the DC permanent magnet motor load improves. Also, a performance analysis was conducted for pure oxygen, and it has been observed that the PEM fuel cell provides a very good performance, even at the reduced supply flow rate of pure oxygen. For this work, a test bench was developed at Kocaeli University (Turkey), which consists of a PEM electrolyzer, a PEM fuel cell, and a DC permanent magnet motor with an air pump. The results of this work will be very useful for comparing the performances of the PEM fuel cell for different air and oxygen (as oxidants) flow rates for the dynamic loads (e.g., fuel cell vehicles with a DC permanent magnet motor). DOI: 10.1061/(ASCE)EY.1943-7897.0000090. (C) 2013 American Society of Civil Engineers.