Although the existing studies on the estimation of corrosion induced cracking time of concrete cover practically assumed that the shape of corrosion product is uniform, experimental observations show that the shape of the corrosion product is considerably localized. In this study, numerical estimation of localized corrosion was accomplished based on the assumption that the main cause of corrosion localization is the variation of chloride ions around the steel. The target case was limited to a two-dimensional corrosion. Analysis results show that the maximum corrosion depth remains about 1.3 similar to 3.5 times deeper than the average corrosion depth after 3.5 years of active corrosion. Parametric study reveals that the diffusion coefficient of chloride ion is the parameter most responsible for corrosion localization. (C) 2007 Elsevier Ltd. All rights reserved.