Description:This book constitutes the thoroughly refereed post-proceedings of the 6th International Bi-Conference Workshop on Agent-Oriented Information Systems, AOIS 2004, held in Riga, Latvia in June and in New York, NY, USA in July 2004. The 15 revised full papers presented have gone through two rounds of reviewing and improvement and were selected from an initial total of 36 submissions. The papers are organized in topical sections on information systems, analysis and modeling, methodologies, and applications.