Identifying the Influential Factors in Sustainable Competitive Advantage through a Resource Based View (RBV) is one of the main and most important ways of creating a sustainable competitive position. The purpose of this paper, therefore, is to identify the CSF in gaining sustainable competitive advantage in Bank Mellat based on A Resource Based View. In order to do this, a conceptual model was developed and based on that, three distinct categories of tangible asset, intangible assets and capabilities were recognized. Also a result was shown that the intangible asset category ranked as the most influential category followed by capability and tangible asset categories. In the tangible category, these factors were identified in the order of importance: variety of services, banking in itself, infrastructure, capital and market. In the competency category, executive competencies and human as well as managerial competencies were identified as influential factors and finally in the intangible category, some internal as well as external factors were identified as having influence in the Sustainable Competitive Advantage of Bank Mellat.