This chapter presents a unified model of Critical Success Factors (CSFs) for ERP implementation projects and the analysis of the relevance of these CSFs along the typical phases of a SAP implementation project. The Accelerated SAP implementation methodology (ASAP) is used as the SAP implementation reference method. Using Process Quality Management method, we derived a matrix of CSFs versus ASAP processes. Then, we evaluated the CSFs relevance along the five ASAP phases, specifically of those ones related with the organizational perspective. The main advantage of our approach is that we unified previous lists of CSFs for ERP implementation projects and we establish the CSFs relevance according to the implementation processes that should be made in a typical SAP implementation project. These findings will help managers to develop better strategies for supervising and controlling SAP or other similar ERP implementation projects.