Initially, the Library of Catalonia was known as the Institut d’Estudis Catalans (IEC), established in 1907. In 1914, the Commonwealth of Catalonia, an institution which comprised four Catalan provincial administrations, opened the library as a cultural and scientific institution. In 1931, the building of the institute, formerly Hospital de Santa Creu, was proclaimed a part of Spain’s historical patrimony, and Barcelona’s municipality granted a large part of the building to the library. In 1936, the library’s first reading room, Sala Cervantina, was opened. In 1939, during the Spanish Civil War, Barcelona fell to the Nationalist forces of General Francisco Franco, and the library was closed for almost a year.

In 1993, the Catalan Library System extended the library’s depository activities and supported its modernisation programme. During the 1990s, the institution underwent major renovation and four underground levels of storage were constructed, adding more than 40 kilometres of shelf space and an annex.

In 2007, the National Library of Catalonia and the libraries of the Monastery of Montserrat, Barcelona Excursionist Centre, Seminary of Barcelona and the Barcelona Athenaeum agreed to participate in the Google Books Library Project, which scans and digitises book collections of the world’s great libraries. The National Library plans to act as a coordinator and intermediary of the other aforementioned libraries. The Catalan libraries group became the second non-Anglo-Saxon group, and the third group in Europe, to join the Google project. Another participant in the books library project includes the Complutense University of Madrid.