Effective project management, such as clear user requirements and top management support, are more conducive to the success of ERP than system innovation. Organizational fit is an important project success factor; however, its importance and relationships with key project management (PM) factors in large-scale software projects have not been thoroughly investigated. The purpose of this paper is to investigate the direct influence of organizational fit factor on ERP success and the moderating influence of organizational adaptation and PM factors on the relationship. We conducted a survey with top 500 enterprises in Taiwan with regard to their ERP implementation experiences. A total of 69 surveys were collected. The collected data were analyzed using the regression analysis. The data analysis results indicate that organizational fit has a direct positive influence on ERP success. Two organizational adaptation factors, including system and business process adaptation, and four key PM factors, including strong teamwork, top management support, end-user training, and counseling capability, play strong moderating roles in the relationship between organizational fit and ERP success. Academic and practical implications on improving ERP success via managing these key factors are drawn from the findings to conclude this research project.