Abstract. The term ‘Master Data’ brings up different interpretations and connotations, especially with vendors espousing the “single version of the truth”. Is there a single version of the truth? Practical realities suggest that we need to continue to live with existing versions – at least until the “single version” is reached. So how do we handle the co-existence of “multiple versions” of the truth? This paper examines a metamodel that defines what master data is, the types of master data, and criteria for determining master data. The metamodel visits master data administration, privileges and master data services including change management, metadata migration and data migration for master data is also reviewed. The impact of changes to an enterprise going the master data route, along with the emphasis to influence future management direction is also examined. Several administration aspects make use of established ISO standards in metadata IS:11179-3 and IS:19763.