The aim of this study is to determine and separate the critical success factors (CSFs) of enterprise requirements planning (ERP) into causes and effects. For this purpose, literature has been reviewed and the branches of a bank have been selected. Based on a pair wise comparison questionnaire relevant to the decision making trial and evaluation (DEMATEL) technique; the collected data has been analysed. Findings indicated that project management, education, commitment and support of the senior managers are among the cause variables and technology infrastructure, planning and business perspective, communications, change management, and participation of the groups are among the effect variables. By applying the approach of this study, service firms such as banks and particularly the studied bank can better implement their ERP projects.