M. Tech. Business Information Systems / Legacy systems are standalone computer applications mostly based on old technologies used in many organizations notwithstanding the availability of more streamlined systems and newer applications. The systems are in place due to the fact that it is costly to replace them, and or they respond adequately to users' requests towards the function they are designed to do. Legacy systems play an important role in today's business because they consist of application programs that may not be upgraded and old data which may not be reformatted to suit new systems. Further, these systems are still alive because of their good pedigree and distinct characteristics. If used in silos, the Legacy systems as part of information systems make the sharing of information, security and management controls, a nightmare. As a result, this affects the process of decision making at the operation and top management levels. Synchronization of reports from the different business units becomes a problem and in the long run the whole business is rendered ineffective and inefficient. This study is calling for the need to integrate legacy systems into enterprise resource planning system. Much as this is so, there is still limited understanding of the factors that contribute to the users' acceptance of the integration of these Legacy systems into an Enterprise Resource Planning System (ERP SYSTEM). This study therefore sought to determine factors influencing users' acceptance of Legacy systems' integration into an ERP System by taking a case of the National Department of Human Settlements.