A reduced nonlinear dynamic two-phase model of a polymer electrolyte membrane fuel cell is presented. The model is derived from a spatially distributed dynamic model and captures the detailed model's multiplicity behaviour. The reduced model is of considerably lower order than the detailed one and requires less computation time. The reduced and the detailed model are compared in steady-state and dynamic simulations. Good agreement is observed. The model can be used to investigate model-based control strategies for PEM fuel cells, especially under operating conditions close to flooding. (C) 2007 Published by Elsevier Ltd.