This paper proposes a methodology based on Analytical Hierarchical Process (AHP) and Fuzzy Inference Systems (FIS), to obtain a better selection of Enterprise Resource Planning (ERP). The company, which are going to acquire the software, bases this selection on their own imposed criteria and the ERPs alternatives based on some supplier's information. To select the most appropriate ERP, at the beginning, AHP was used. Then, Through a FIS is evaluated the selected ERP to know if it comply with the business financial and operational performance. Finally, another FIS fuses these results in an only one, which is called 'acceptability level'. The proposed methodology try to quantify all the subjectivity that involve an ERP acquisition by a business.