One of the key basics for IMD's work and services are the library and the archive. The public holding contains more than 40,000 scores of contemporary music and 5.000 scholarly writings on the music of the twentieth and twenty-first centuries.

The archive concentrates on the documentation of the International Summer Courses from the 1940s until today. It includes almost the complete sound recordings of the concerts and lectures that were held during the summer courses, the record collection, the substantial photo archive and the collection of letters.
In a large digitization project, extended over several years, IMD captures and describes the precious archive inventory of the International Summer Course for New Music with the aim of a future online search function.