Master Data Management (MDM) solutions provide the framework for delivering access to integrated data across the full Well lifecycle and, as such, have become a critical success factor for E&P companies. However, different groups of people within a company create and consume data at different Well levels depending upon their role. Effective integration of this data requires the ability to uniquely identify and relate a Well and all of its components at all levels. The resulting Well Hierarchy enables Well data to be integrated at the correct level across the full Well lifecycle and provides the foundation for successful master data management. This presentation details one approach to establishing the Well Hierarchy as a foundation for MDM. The findings are supported through a case study of a practical implementation.