This book constitutes the refereed proceedings of the 15th International Conference on Advanced Information Systems Engineering, CaiSE 2003, held in Klagenfurt, Austria in June 2003. The 45 revised full papers presented together with 3 invited contributions were carefully reviewed and selected from 219 submissions. The papers are organized in topical sections on XML, methods and models for information systems, UML, Internet business and social modeling, peer-to-peer systems, ontology-based methods, advanced design of information systems, knowledge, knowledge management, Web services, data warehouses, electronic agreements and workflow, requirements engineering, metrics and method engineering, and agent technologies and advanced environments.