Computer Music Modeling and Retrieval 2009 was the sixth event of this - ternational conference series that was initiated in 2003. Since the start, this conference has been co-organized by the University of Aalborg, Esbjerg, D- mark (http://www. aaue. dk) and the Laboratoire de M' ecanique et d'Acoustique inMarseille,France(http://www. lma. cnrs-mrs. fr)andhastakenplaceinFrance, ItalyandDenmark. The?vepreviouseditionsofCMMRo?eredavariedoverview of recent years' music information retrieval and sound modeling activities in addition to alternative ?elds related to human interaction, perception and c- nition, as well as philosophical aspects linked to the ?eld. We believe that the strength and the originality of this international conference both lie in its mul- disciplinary concept and its ability to permanently evolve and open for new trends and directions within the related ?elds of interest. This year's CMMR took place in Copenhagen, Denmark, May 18-22, 2009 and was associated with theInternationalConferenceonAuditoryDisplay(http://www. icad. org),hereby introducing new topics related to sound design, soni?cation and augmented - ality to the computer music modeling and retrieval community.