Three types of stack structure designs of polymer electrolyte membrane electrolyte fuel cells (PEMFCs) were reviewed and evaluated under various humidities and temperatures, including bipolar, pseudo bipolar and monopolar (strip) stacks. The bipolar stack design is suitable for delivering moderate to high power, but if a single cell fails it may lead to a loss of power for the whole stack. Water, heat, fuel and air management is required in bipolar plate design. For the pseudo-bipolar cell stack design it is easy to achieve high power by simple addition of more bi-cell units, but each bi-cell has to be filled with fuel and air separately. In the monopolar cell stack design a common gas flow field is shared by a whole strip, when a single cell fails the stack performance will not be affected seriously. Monopolar cell stack design is suitable for applications in low power and high voltage devices because of its high internal resistance.