In 1964, the library and the archives moved to a separate building behind the newly erected Ecumenical Centre in Grand-Saconnex. The premises to host the library and archives had been financed by a donation of Jeanette Watson in 1959, in memory of her husband Thomas J. Watson, the founder of IBM.
The first professional archivist joined the librarians' team in 1987. In 2003 a generous donation by a well-known financial institution in Geneva permitted to modernize the equipment of the library and the archives and to make the inventories and the catalogs available online. Specialists in audiovisual archives could also be hired for this important project.
After the consolidation of the library on one single site at the Ecumenical Institute in Bossey in 2012, the archives moved in the newly arranged Espace Archives in a wing of the former library building a year later. Two archivists take care and custody of the fonds stored in the basement, answer the various requests and support researchers in the reading room.