Background and problem discussion: The function of the controller is said to have changed from being the corporate police to become the business partner, depending on a number of different reasons. The amount of empirical and theoretical literature explaining why this change has occurred is considered to be limited. The development of information and communication technologies have had an impact, but so far the relationship between the controller and information systems have not been fully established. Tetra Pak has a complex structure of information systems but there is a lack of knowledge on how these affect the function of the controller whether it is in core or support operations.

Objective: The objective of this study is to identify the controller's function within Tetra Pak’s core and support operations. Furthermore, to explore and analyse what impact information systems have on the controller's function within Tetra Pak’s core and support operations.

Method: The study is characterized by a deductive approach and a case study is carried out at Tetra Pak. Nine semi-structured interviews with different controllers in the core and support operations have contributed to the empirical material. The theoretical framework has been collected through scientific articles and literature.

Conclusion: The corporate police, the business partner and the strong controller was identified in both core and support operations. A new type of controller was identified as a system controller. The impacts of information systems on the corporate police in core and support operations were minimal. It had a larger extent of impact on the business partner and the strong controller in both core and support operations. This was due to flaws in both system quality and information quality characterized by lack of information and full access which made certain processes ineffective.