Atomistic modeling has been used to study the structure and transport properties of surface oxide films on pure iron. These calculations have been used to constrain parameters in two common models for oxide growth kinetics, i.e., the high-field model and diffusion- limited growth. Empirically determined parameters for these models are not consistent with the atomistic modeling. However, if cation transport is dominated by grain- boundary diffusion, these growth models can be reconciled with the atomistic modeling. (c) 2005 The Electrochemical Society. [DOI: 10.1149/1.1940787] All rights reserved.