The Working Group’s DACS supplement provides guidance to music archivists and librarians in applying a descriptive standard developed for general archival collections to music collections. In the session, Working Group members will explain the rationale behind the Group’s charge, their approach to creating the supplement, and how it will benefit both music librarians and archivists. The Music Library Association’s Working Group for Archival Description of Music Materials has developed a supplement that bridges the descriptive gap between Describing Archives: A Content Standard (DACS) and the specific needs of music materials. DACS is the content standard used by archivists in the United States to describe archival collections and thereby provide access to them. However, DACS does not give specific instructions regarding description of archival notated music.sts with responsibility for archival collections. Session attendees will learn how to make decisions about archival description of music scores and how different levels and types of archival description reflect these decisions.