This paper summarizes the recent PEM fuel cell models developed at the University of Miami. In the last a few years, several mathematical models for PEM fuel cells have been developed at the University of Miami. The main thrust has been the development of models that are capable of simulating fuel cell performance without prescribing arbitrary/approximate boundary conditions at the interfaces between the different layers of the fuel cell sandwich. By solving transport equations and the equations for electrochemical reactions and current density with membrane phase potential in unified domains, polarization curves under various operating conditions were obtained. The modeling results also show the variations of species concentration and current density in the directions of the channels and across the channels.