This book constitutes the proceedings of the 6th International Conference on Web Information Systems Engineering, WISE 2005, held in New York, NY, USA, in November 2005. The 30 revised full papers and 20 revised short papers presented together with 18 poster papers were carefully reviewed and selected from 259 submissions. The papers are organized in topical sections on Web mining, Web information retrieval, metadata management, ontology and semantic Web, XML, Web service method, Web service structure, collaborative methodology, P2P, ubiquitous and mobile, document retrieval applications, Web services and e-commerce, recommendation and Web information extraction, P2P, grid and distributed management, and advanced issues. The presentation is rounded off by 14 industrial papers and the abstracts of 4 tutorial sessions.