This book constitutes the refereed proceedings of the 6th Asia-Pacific Web Conference, APWeb 2004, held in Hangzhou, China, in April 2004. The 60 revised full papers, 24 revised short papers, 15 revised poster papers, and 3 revised industrial papers presented together with 3 keynote papers and 3 invited papers were carefully reviewed and selected from 386 full paper submissions. The papers are organized in topical sections on web semantics, web personalization, web intelligence, XML processing, XML and Databases, P2P systems and applications, grid computing and networking, web-based query processing, advanced query processing, advanced applications, knowledge discovery and pattern recognition, web mining, data mining and data analysis, text mining, information retrieval, web services and web computing, web safety, web technologies, web caching and mobile objects, workflow management, and e-commerce.