Abstract
It is said that cooperation and consistency among the user company's management, user department, and IT department are important when implementing an information system. In recent years, fewer companies have attempted to implement information systems independently, and have instead chosen to outsource to vendor companies for implementation. Therefore, it is considered that the capability of vendor companies also affects the performance of information system implementation. This study conducted an exploratory case study of six Japanese companies that have implemented enterprise systems. The results of the case studies indicate that the IT capability of both the user companies and the vendor companies affects their performance when implementing enterprise systems.