The main purpose of this study was to assess the performance of branches of Refah Bank in Tehran. The study is a descriptive survey with regard to methodology and nature. Reviewing the theoretical literature, the researcher tried to present a three-level theoretical model to analyze the efficiency and customer loyalty in Refah Bank. In this study, 2 inputs (operating costs and the number of employees) and 6 outputs (assessment of employees, customer loyalty, customer satisfaction, the number of opened accounts, the number of loans given and the amount customer expectations are met) were used to assess the efficiency of branches. The results indicated that customer satisfaction and the amount customer expectations are met have maximum weight or priority in achieving efficiency among recognized factors. The researcher investigated efficient units using a combination of fuzzy Data Envelopment Analysis (DEA) and fuzzy Analytic Hierarchy Process (AHP).