There has been growing interest in the modelling of proton exchange membrane fuel cells (PEMFC). While some steady-state models have been proposed, literature is scarce in PEMFC two-phase dynamic models and transient studies. Typical dynamic models for the fuel cell are empirical current-voltage dynamic models. The internal transients associated with reactant and product species and other components are usually neglected. Further, systems engineering studies such as process control, dynamic optimization, identification of faults and other operational problems in fuel cell studies are missing to a large extent. A detailed dynamic model for spherical agglomerate in a PEMFC is presented in this work. The dynamic model will include detailed mathematical equations for O2 and H+ ions. The model will be unique from the earlier proposed models, as it will include not only the dynamics, but also detailed mathematical equations for transport and electrochemical kinetics. Preliminary results using the dynamic model of spherical agglomerate are presented in this paper. © 2005 Elsevier B.V. All rights reserved.