To overcome rapidly changing business environment, companies are focusing on their core business areas. Outsourcing in general has become a standard to sustain competitive advantage. ASP(Application Service Provider) service, another form of IT outsourcing, is business model for providing a contractual service offering to deploy, host, manage and rent access to an application from a centrally managed facility. The main purpose of this study is to investigate on the factors contributing to the success of ASP services by conducting an empirical research to enterprises using ASP service. For this purpose, we developed a research model based on the literature reviews of ASP services, IT outsourcing, and relational exchange. A total of 106 usable survey responses has been used in the analysis. The unit of analysis was relationship and respondents were person in charge of ASP service of each corporation. The findings indicates that (1) service tangibles, customization, partnership, IS maturity and monitoring of the vendor had an positive influence upon non-economic benefits, (2) service tangibles, IS maturity and monitoring of the vendor had an positive influence upon economic benefits, and (3) service tangibles, reliability, partnership and monitoring of the vendor had positive influence upon satisfaction about outcomes of relationships.