Anodized alumina templates have emerged as an important material system for the low-cost fabrication of semiconductor and metal nanostructure arrays. This material system uses natural self-organization for the creation of periodic arrays of nanoscale structures. In spite of the extensive experimental investigations reported in the literature, the theoretical mechanisms, and their dependence on process parameters such as current density and electrolytes, are not well understood. In this article, we propose a theoretical model based on the rate equation approach in which both the alumina formation and etching are considered. This model employs a minimal number of parameters and yet captures the essence of the experimental observations with sulfuric acid as the electrolyte and can be used as a predictive tool for process selection. (C) 2004 The Electrochemical Society.