In this paper we analyze the role of Enterprise System (ES) in shaping a company’s transformation process by conducting an in-depth case study in a large European high-tech company. Although there are previous studies concerning organizational transformation and ES implementation process, the role of ES as an instrument for de-institutionalization is not well understood. By drawing on the framework of neo-institutional theory we seek to understand how ES facilitates discarding of the old ways of doing things and the simultaneous forming of the new institutional arrangements. This paper seeks to provide valuable insights into the de-institutionalization process and the role of ES in a company’s reorganization. The findings show how ES in use serves as an agent and a platform for de-institutionalization and later as a powerful force in forming the new institutional arrangement.