A novel model for the potentiostatic discharge of primary alkaline battery cathodes is presented. The model is used to simulate discharges resulting from the stepped potential electrochemical spectroscopy (SPECS) of primary alkaline battery cathodes and the results are validated with experimental data. We show that a model based on a single (or mean) reaction framework can be used to simulate multireaction discharge behavior, and we develop a consistent functional modification to the kinetic equation of the model that allows for this to occur. The model is used to investigate the effects that the initial exchange current density, i(0)(0), and the diffusion coefficient for protons in electrolytic manganese dioxide (EMD), DH+, have on the SPECS discharge. The behavior observed is consistent with the idea that individual reduction reactions, within the multireaction, reduction behavior of EMD, have distinct i(0)(0) and DH+ values. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3505003] All rights reserved.