The Foundation's archive is composed of numerous collections on the history of the 20th century Church. In 1995 the Superintendent of Archives in Emilia Romagna declared it of significant historical interest.
The archive began with the foundational material and effort of the Centro di Documentazione, and was further enriched by the arrival of Giuseppe Dossetti's and Cardinal Giacomo Lercaro's papers. It expanded during the research carried out during the Vatican II and has since become one of the most remarkable collections of documents on conciliar events in the world. Other collections found in the archive include the Cronache Sociali Collection; the Mons. Angelo Spadoni Collection; the Don Alberto Altana Collection; the Don Lorenzo Milani Collection, and the Pierre Duprey Collection. The archive continues to acquire paper documents and, more recently, television and cinema resources related to the Church and 20th century history.