Growth of the collections was to speed up during the 20th century, which can be seen in all comparable libraries, following the general increase in printing. The Bastions building quickly proved too cramped and extensions and transformations were to punctuate the entire century. In 1905 a new reading room was built right up against the eastern façade, while exhibition galleries were added. Several refittings of the underground book storage increased their capacity. The last one to date was completed in 1987.
The most recent period witnessed the gradual introduction of computer technology into the various library departments. In 1984, the Bibliothèque was made a part of the Réseau romand, the Western Swiss network, which is known today as Rero, the Réseau des bibliothèques de Suisse occidentale, or Library network of Western Switzerland.
In 1999 the Bibliothèque de Genève inaugurated the first open-access area in its history. Prior to that, except for reference works and other specialized books for ready consultation, library books could only be obtained by doing a catalogue search and having them retrieved from the storage shelves. Despite its limited size (30,000 volumes), this encyclopedic selection of recent books has been a great success, which is attested by the volume of books in circulation.
The Reading room was renovated in 2005, offering readers greater comfort and WiFi access, the first public hotspot in the City of Geneva.
In 2006, the Bibliothèque mounted a major exhibition at the Musée Rath, Arts, savoirs, mémoire. Trésors de la Bibliothèque de Genève (Arts, knowledge, memory. Treasures of the Bibliothèque de Genève). It was at this occasion that the library officially readopted its former name, the Bibliothèque de Genève.
A complete renovation of the Espace Ami-Lullin, the exhibition space located on the Bibliothèque’s ground floor, was begun in 2007. Since its inauguration in October 2008, the room’s furnishings and equipment, now entirely redone, make it possible to display items in an utterly secure environment. The exhibition space has also been provided with an area where talks can be given.
In the early 21st century, renovation work was undertaken, although without resolving the problem of spatial limits for the collections in the medium term (over 2,000,000 volumes for printed books alone).