This book constitutes the refereed proceedings of the 16th International Conference on Advanced Information Systems Engineering, CAiSE 2004, held in Riga, Latvia in June 2004. talks were carefully reviewed and selected from 160 submissions. The papers are organized in topical sections on enterprise modeling, data integration, conceptual modeling, workflows, methodologies for IS development, databases, methodologies for IS development, databases, support for collaboration between individuals and organizsations, Web-based systems, requirements engineering, ontologies, and data warehousing.