Enterprise Resource Planning (ERP), systems are high technical cross-functional information systems that designed to improve organizational performance and competitiveness by streamlining business processes and eliminating duplication of works and data. Regarding the fact that ERP systems have a tremendous advantage for organizations but the implementation of an ERP is not straightforward and it involves significant risks. Several studies have conducted to identify the critical success factors (CSFs) in the ERP implementation process. However, most of those studies are lacking in systematic efforts to classify and evaluating CSFs. This study is motivated by a lack of theoretically research in the classification and evaluating CSFs by considering the causal relationship among CSFs that are affected the successful implementation of ERP systems. To achieve this aim Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytical Network Process (ANP) is applied. The proposed methodology implemented in the biggest refrigerator production company in Iran.