Recently ERP(Enterprise Resource Planning) package has been on of important issues in developing information systems in many Korean companies. The main objectives of this study are to analyse the case of implementing ERP system in Samsung Display Devices Co. which is rated to be successful, and to derive significant implications for effective ERP implementation. First, this study focused on showing the detailed roadmap of performing ERP implementation project which largely consists of 5 stages(planning and organizing, visioning. process redesign and mapping, testing and arrangement, and installation and roll-out to overseas subsidiaries), and explaining key activities in each stage. Second, the performance of this project was evaluated on the basis of both process-centered critieria and result-centered ones. Finally, this study intended to discuss and explicate the bottlenecks and the critical success factors in implementing this project. The findings of this case study are thought not only to be useful as a practical guideline in carrying out ERP implementation project but also to provide significant basis for constructing the theoretical framework of effective ERP implementation.