Data quality management plays a critical role in all kinds of organizations. High-quality data is one of the most important prerequisites for making strategic business decisions and executing business processes. In order to be able to assess data quality, ensure efficient process execution, and verify the effectiveness of data quality initiatives, data quality has to be monitored and controlled. This can be achieved by implementing a comprehensive controlling system for data quality. However, only few organizations have managed to implement such a system. This paper presents a single-case study describing the process of implementing a comprehensive data quality controlling system. The study focuses on controlling activities defined in the field of business management.