The archival section with a total length of 6.000 meters constitutes with the library the main part of the collections of the Liberaal Archief.

The Liberaal Archief preserves the archives of the major liberal organizations such as the liberal party, the Willemsfonds (the oldest, still active cultural organization in the country), the Liberaal Vlaams Verbond (a pressure group of Flemish liberals) and the Liberale Jonge Wachten/PVV-Jongeren (the young liberals). Archives of individuals active in the liberal movement are kept as well.

Records of more than 1,000 local associations in Flanders are available. These include political organizations (local sections of the party), societies active in the cultural sphere (local sections of the Willemsfonds; brass bands; dramatic clubs and choral societies; writers and sports clubs); social and charitable organizations (local divisions of trade union); and specific groups (women's, youth, and students organizations).

Regarding international liberalism the Liberaal Archief keeps documents of the Liberal International and the Mont Pèlerin Society (see: Inventories).

Every effort is made to make the archives accessible for research. Considering the rapid increase of the collections, archives are made quickly accessible through storage lists. Inventories are made in a second phase. A survey of the published inventories is available in the section Publications.

Archives may be donated or entrusted. Restrictions concerning consultation of the deposited archives can be included by mutual agreement.

The following collections are, among others, available for consultation:

• All the congresses of the liberal party from 1846 till now.
• The records of the meetings of the Party bureau from 1927 till 1972; these records are thematically indexed.
• All the periodical party publications (Liberaal Leven/Vie Libérale, Demain Politique, Progrès/Vooruitgang, PVV-Flitsen, PVV-Magazine, Vrij, De Burgerkrant).
• Of a few local party sections the conference records date back to the 1850's (Deinze 1857-1901; Ninove 1857-63; Kortrijk 1861-1919).
• Documents concerning the elections are available from 1847; the collection is representative after the Second World War (a summarized survey is being prepared).
• The complete archive of the Willemsfonds since its foundation in 1851; the 19th century correspondence is completely inventoried.