Enterprise resource planning (ERP) systems, if implemented correctly, have shown that a firm can gain strategic and tactical advantages over their competition who do not implement such systems. However, with failure rates estimated to be as high as 50% of all ERP implementations, companies can be negatively impacted by a poorly performing ERP system. The research on ERP has focused on events leading to the selection, evaluation, and implementation of the ERP system. The intent of this updated research effort is to capture new theories that can help practitioners successfully manage ERP systems by performing a post-ERP implementation examination of eight corporations and a pertinent research review. This chapter is based on a qualitative research design involving case-study methodology. The propositions derived from the case study form a broad set of considerations that influence the success of an ERP system.