The Mundaneum houses a large collection of documents on anarchism.

The collection was started by Walter Théodore Glineur (1887-?). An anarchist, from the 1930s onwards, Glineur contributed to the activities of the Mundaneum by compiling a vast collection of documents on anarchism, dating from the 1840s to the late 20th century. This collection, which has been added to, is particularly valuable because the very nature of the anarchist movement — disparate and subject to repression — meant that sources on the subject were often scarce and dispersed.

The Mundaneum also holds other resources on the movement including some of the archives of Marcel Dieu (1902-1969). Better known under his pseudonym, Hem Day, he was a key player in the Belgian anarchist movement.