Mathematical modeling and numerical simulation can help increasing the efficiency, energy and power density of zinc-silver oxide batteries. It is clear that the accuracy of the modeling depends on the assumptions of the model. Among the different types of modeling, the models based on governing equation can give a very good understanding of the involved physical phenomena. Although zinc-silver oxide batteries are very mature, there do not appear to be many existing modeling based on fundamental governing equations. In the present work, a general system of governing equations for this type of batteries is presented based on the single-domain approach. The main advantage of this type of modeling is that it contains a single-domain formulation which is valid on entire cell sandwich, namely porous electrodes, separator, electrolyte reservoir and separator. The presented governing equations are solved numerically and the results are compared and verified with experimental tests. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.038212jes] All rights reserved.