Public sectors need to manage data for internal and external use is growing. Master data management aims to manage the core data that affects generally the data quality in large extent. The objective of the research is to observe the factors that affect the architectural decisions when establishing a MDM function. This is done though prior research and a case study in a municipality. Business needs and the existing IT environment indicate the best usage scenario for MDM. Scenario indicates the suitable architectural implementation style and also helps the organization to comprehend what they should emphasize in their development.