The International Conference on Case-Based Reasoning (ICCBR) is the p- eminent international meeting on case-based reasoning (CBR). ICCBR 2005 (http: //www.iccbr.org/iccbr05/) was the sixth in this series of biennial - ternationalconferenceshighlightingthemostsigni?cantcontributionstothe?eld of CBR. The conference took place during August 23-26, 2005 at the downtown campus of DePaul University, in the heart of Chicago's downtown "Loop." P- vious ICCBR conferences were held in Trondheim, Norway (2003), Vancouver, Canada (2001), Seeon, Germany(1999), Providence, Rhode Island, USA (1997), and Sesimbra, Portugal (1995). Day 1 of ICCBR 2005 was Industry Day, which provided real-world expe- ences utilizing CBR in ?elded applications.Day 2 featuredvarious workshopson CBR in the health sciences, textual case-based reasoning, computer gaming and simulation environments, and similarities - Processes- Work?ows.Days 3 and4 comprisedpresentationsandpostersontheoreticalandappliedCBRresearch, as well as invited talks from three distinguished scholars: Derek Bridge, University College Cork, Craig Knoblock, University of Southern California, and Colleen Seifert, University of Michigan. The presentationsand posterscovereda wide rangeof CBR topics, including adaptation, applications, case base maintenance, computer games, creative r- soning, knowledge representation, interactive systems, knowledge management, knowledgeacquisition, multiagentcollaborativesystems, similarity, tutorings- tems, bioinformatics, and textual CBR.