The library's holdings have increased rapidly since its establishing in 1919. Today the library holds more than 114,000 items. Such a rich collection was built with several purchases as well as donations from different members of Slovene and Slavonic academia. Among others, the donators and collectors have included Maks Pleteršnik, Rajko Nahtigal, France Kidrič, Fran Ramovš.
The library also takes care for ordering books, reference literature, and other library material from the West Slavic, South Slavic and East Slavic language regions.