The concept of IT as a powerful competitive weapon has been strongly emphasized in the literature, yet the sustainability of the competitive advantage provided by IT applications is not well-explained. This work discusses the resource-based theory as a means of analyzing sustainability and develops a model founded on this resource-based view of the firm. This model is then applied to four attributes of IT-capital requirements, proprietary technology, technical IT skills, and managerial IT skills- which might be sources of sustained competitive advantage. From this resource-based analysis, we conclude that managerial IT skills is the only one of these attributes that can provide sustainability.