This paper describes an overview of design and implementation of Union Serial System using Dublin Core (DC) Metadata. The project of developing Union Serial System was for making a better research information service environment leaded by Korea & Education Research Information Services (KERIS). In this project, we define the qualifiers and additional data elements for locally specific application based on DC Metadata. All the records in the Union Serial System were originated from university library as MARC, which was converted into DC Metadata. In this paper, we will include the process of designing Union Serial System, data model with Metadata element set, qualifiers, mapping MARC into DC Metadata, system architecture, and tribulations in this project.