Since its establishment in Hong Kong in 1998,the international Intelligent Data Engineering and Automated Learning (IDEAL) conference has become a r- erence for researchers in both theoretical and practical aspects of learning and information processing, data mining, retrieval and management, bioinformatics and bio-inspired models, agents and hybrid systems and ?nancial engineering. The purpose of IDEAL conferences has been to provide a broad and interd- ciplinary forum for scientists, researchers, and practitioners in these areas from around the world. A special feature of IDEAL conferences is cross-disciplinary exchange of ideas in emerging topics and application in these areas. Data ana- sis and engineering and associated learning paradigms are playing increasingly important roles in an increasing number of applications and ?elds. The mul- disciplinary nature of contemporary research is pushing the boundaries and one of the principal aims of the IDEAL conferences is to promote interactions and collaborations across disciplines. This volume of Lecture Notes in Computer Science contains accepted - pers presented at IDEAL 2006 held at the University of Burgos, Spain, during, September 20–23, 2006. The conference received 557 submissions from over 40 countriesaroundtheworld,whichweresubsequentlyrefereedbytheProgramme Committeeandmanyadditionalreviewers.Afterrigorousreview,170top-quality papers were accepted and included in the proceedings. The acceptance rate was only 30%, which ensured an extremely high-quality standard of the conference. The buoyant number of submitted papers is a clear proof of the vitality and increased importance of the ?elds related to IDEAL, and is also an indication of the rising popularity of the IDEAL conferences.