Abstract-Enterprise Resource Planning (ERP) systems have established a reputation in the world of business as indispensables tools that integrate all departments and functions across a company into a single computer system. However, implementing an ERP system does not always result in enhanced organizational performance. In order to ensure successful implementation, companies should study the critical factors having an impact on the whole procedure. In this context, the present study proceeds in developing and testing an original conceptual framework (research model), which explores the factors having an impact on ERP implementation success (internal environment, technology-related issues, implementation team, end-users), as well as the impact of the implementation itself on organisational performance. The proposed conceptual framework was tested, using a newlydeveloped structured questionnaire, in a sample of 204 Greek companies that have already implemented an ERP system. Enterprise Resource Planning (ERP) systems are software systems which can be customized to integrate the business processes of a company, in such a way, that they are visible and accessible by the management in real-time [4]. An ERP system, designed to serve the modern sophisticated management, enables its users to coordinate key business practices across functions more efficiently, collect corporate data more holistically and offer optimal control over the operations of the organisation [5].When an ERP system is successfully implemented, it promises to manage and integrate all business processes and functions within an organization [6] [7]. The integration, brought by ERP implementation, helps organizations to increase This work was not supported by any organization. and improve their overall market position, in order to gain competitiveness in a rapidly changing business environment [ 8 ] . I t a l s o h e l p s d i f f e r e n t d i v i s i o n s s h a r e d a t a a n d knowledge, reduce costs and improve management of business processes [9] [10].Due to the potential benefits of ERP systems, most of the organizations invested both time and money in their implementation [11]. However, ERPs have a reputation of costing a lot of money and providing limited results [10]. Some of the causes, cited in the relevant literature, for failed ERP projects include: poor project management planning, lack of business management support, unexpected return on investments, insufficient education and training, and, finally, weakness to redesign business processes [12] [23]. Despite that, the literature review analysis that has been conducted, failed to identify any empirical studies adopting a multidimensional approach, incorporating both antecedents and outcomes.The present study aspires to bridge that gap in the relevant literature, developing and testing a threedimensional conceptual framework (research model). More specifically, the first dimension includes the antecedents of ERP successful implementation (internal environment, technology-related issues,...