When a proton exchange membrane fuel cell (PEMFC) system is operated in the dead-ended anode mode, nitrogen will gradually permeate from the cathode to the anode. The accumulation of nitrogen in the anode causes a performance drop, which can be recovered by purging. The purge strategy depends on operating conditions of the PEMFC. To investigate the effect of operating conditions on the performance of a PEMFC with a dead-ended anode, a mathematical model is developed to estimate the nitrogen crossover and accumulation in the anode of the PEMFC, especially for varying-load operations. The effect of operating current density on nitrogen crossover is coupled in the model. Parameters in the model are calibrated according to experimental data. The experiments are designed to measure the voltage variations of the single cell with dead-ended anode at different operating current densities. The effect of current density on purge frequency and voltage variation is shown. Simulation results by this calibrated model agree well with experimental data. The transient of hydrogen concentration in the anode is investigated by the model. A purge strategy is suggested at the end of this study. (C) 2014 Elsevier Ltd. All rights reserved.