Recently, ERP system is used as a important tool of management innovation for enterprise's survival and development. It is very important to recognize how much influence to organizational performance through ERP system implementation. The purpose of this study is to find out the impact of environmental, organizational, information systems characteristics on successful implementation of ERP systems in Korean SMEs(Small and Medium Enterprises). From previous researches on ERP adoption and implementation, 7 independent variables (competitiveness, government support, top management support, process innovation, project management, IS maturity, and ERP customizing), and 1 dependent variables (successful implementation of ERP systems) are identified. 3 questionnaires were removed from the study because of missing or inappropriate responses, and final samples are 91 SMEs. The results of hypothesis testing show that determinants of successful implementation of ERP systems are top management support and IS maturity. Five variables such as competitiveness, government support, process innovation, project management, and ERP customizing do not significantly influence to successful implementation of ERP systems. The contribution of this study is that it provides an empirical evidence of the causal relationship between ERP adoption factor and ERP success. This study showed that top management support and IS maturity are essential to accomplish successful ERP implementation for SMEs.