Data quality management plays a critical role in all kinds of organizations. Data is one of the most important criteria for strategic business decisions within organizations and the foundation for the execution of business processes. For the assessment of a company's data quality, to ensure the process execution and to monitor 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. The implementation of such a system has been realized in only a few organizations. This paper presents a single case study describing the implementation of a comprehensive data quality controlling system. The study focuses on controlling activities defined in the fields of business management.