Information Systems (IS) auditing has been know to be helpful in developing optimal IS and managing information resources successfully. The public sector of Korea has witnessed the rapidly growing demand for IS auditing. However, there is a dearth of research that evaluate the effects of IS auditing. This study assesses the impacts of IS auditing based on a process perspective. In order to evaluate the effects objectively and properly, the current study collected empirical data from 58 firms. This stuuy confirmed that IS auditing was a very effective tool for successful IS implementation. The results show that IS auditing improves “project management”, “support”, and “engineering” practices while it does not make any impact on “contract” practice. In general, IS auditing has a tremendous impact on facilitating organization’quality improvement efforts.