An experimental study is carried out to investigate effects of stack orientation and vibration on the performance of Proton Exchange Membrane (PEM) fuel cell. A 25-cm(2) single cell with serpentine anode and straight cathode flow channels is used. The hydrogen flow rate, cathode air temperature, and relative humidity are kept constant at 60smL/min, 20 degrees C and 80%, respectively, whereas the cathode air flow rate values are 220, 440, and 660smL/min as well as free breathing case. An orientation and vibration mechanisms are designed to facilitate different values orientation positions and vibration amplitude and frequency of the stack. The results show that stack orientation and vibration have significant effects on the performance of PEM fuel cell. Based on the results obtained from this study, it can be concluded that optimum positions of cell orientation are 30 degrees and 90 degrees at low and high values of cathode air flow rate, respectively. Also, an improvement in the performance of the fuel cell is achieved when the stack is vibrated with low values of amplitude and frequency. Each of cell maximum power density and maximum hydrogen utilization decreases with increasing each of amplitude and frequency of stack vibration. Copyright (c) 2014 John Wiley & Sons, Ltd.