Though financial services outsourcing has been increasing during the last decades, most outsourcing projects have failed due to qualitative criteria used in decision-making as well as being unaware of differences in environmental circumstances. This study aims at designing a model of deciding on outsourcing in state banks. The data of this applied, developmental research was collected, using descriptive-survey method and two instruments, namely, interview and quantitative were used in qualitative and quantitative sections, respectively. The sample of the study comprises of banking experts working in six state banks and the Central Bank of Iran. The initial model was derived, based on an analysis of the aspects of variables as well as the indices obtained from the theoretical principles and previous studies. The final research model, which consists of 6 factors and 22 subfactors was developed, using the Fuzzy Delphi Method and in triple consultation with 20 banking experts. The criteria were weighted, and the relationship between the criteria was examined, using F-DEMATEL method and ANP. The results of the study indicate that the following are the most significant criteria driving the decisions made by state banks on activities outsourcing: reliance on service providers, cost, the rapid delivery of services by the contractors, gaining competitive advantage, the existence of multiple contractors, improved control and overseeing.