This paper presents a mathematical model for the analysis of both dynamic and steady-state characteristics of a 500 W proton exchange membrane fuel cell (PEMFC). A DC-to-DC converter is connected to the output of the studied PEMFC for stabilizing voltage and current fluctuations under different loading conditions. Dynamic performance of the combined PEMFC and DC-to-DC converter subject to a sudden partial load insertion followed by a load rejection is performed and analyzed. The cell polarization curves of the studied PEMFC under various steady-state conditions are also carried out. The analyzed results show that the proposed model is feasible to access both dynamic and steady-state characteristics of a PEMFC under various loading conditions.