Conceptual modeling has long been recognized as the primary means to enable so- ware development in information systems and data engineering. Conceptual modeling provides languages, methods and tools to understand and represent the application domain; to elicit, conceptualize and formalize system requirements and user needs; to communicate systems designs to all stakeholders; and to formally verify and validate systems design on high levels of abstraction. The International Conference on Conceptual Modeling provides a premiere forum for presenting and discussing current research and applications in which the major emphasis is on conceptual modeling. Topics of interest span the entire spectrum of conceptual modeling including research and practice in areas such as theories of concepts and ontologies underlying conceptual modeling, methods and tools for - veloping and communicating conceptual models, and techniques for transforming conceptual models into effective implementations. The scientific program of ER 2008 featured several activities running in parallel. The core activity was the presentation of the 33 research papers published in this volume, which were selected by a large Program Committee (PC) Co-chaired by Qing Li, Stefano Spaccapietra and Eric Yu. We thank the PC Co-chairs, the PC members and the additional referees for the hard work done, often within a short time. Thanks are also due to Moira Norrie from ETH Zurich, Oscar Pastor from the Universitat Politècnica de València, and Amit Sheth from the Wright State Univ- sity for accepting our invitation to present keynotes.