The objective of this work is to compare different modeling studies of Proton Exchange Membrane Fuel Cells, and different approaches to the problem of water and thermal management. The rationale of this review is to eludicate the mass transport limitation in a fuel cell when operating with air as a cathodic reactant. Some of the important conclusions from this study are : (i) the modification of the structure of the electrode to increase the diffusion of oxygen should lead to a significant enhancement of the performance; and (ii) it is possible to solve simultaneously the problem of water and thermal management using an air plus evaporative cooling method.