After the Library had been established, the collection was enriched by gifts, mostly from foreign universities and foundations, as well as from individuals. When the University Library moved into a new building, the collection contained 57.254 items. Until the Second World War, the collection grew owing to various valuable legacies received, reparation payments from Germany, the purchase of important library collections that had belonged to scientists and prominent cultural figures, and the acquisition of books and handbook manuals necessary for Library users. Before the Second World War the collection contained 318.772 items.
From October 1944 to 1963 (due to the fact that the National Library of Serbia was destroyed in the bombing of 6th April 1941), the University Library was entitled to receive a compulsory copy of any book published in Serbia. Numerous gifts were received from the country and from abroad, exchange with many Yugoslav and foreign academic libraries began, and due to a permanent fund for book acquisition the Library collection was greatly enriched. Until 1944, the acquisition was oriented mainly towards publications in the sphere of the humanities in French and German, but after that the acquisition of all scientific publications was intensified, including publications in English and Russian. At the end of the year 2000 the collection contained 1.448.245 items.
The Library collection contains a large number of publications from the humanities and natural sciences. The most important scientific works, reference works, both domestic and foreign (encyclopedias, bibliographies and dictionaries), professional and scientific journals, domestic and foreign university publications and a large collection of Ph.D. theses are kept there.
The serial collection contains over 8,500 titles in 700,000 volumes. About 5,200 titles are foreign serials, mostly in English, German, French and Russian. Because of financial problems, the greater part of the serial collection is acquired through exchange and gifts. From the end of 2000, the Library has gained a licence for EBSCO, which contains databases with several thousand electronic full-text editions of social science and medical journals, and the general intention is to acquire licences for journals in other scientific fields.
The Department of Old and Rare Books contains manuscripts, old and rare printed books, old journals and papers, archive collections, a map collection, M.A., M.Sc. and Ph.D. theses, specialist papers.
The collections of manuscripts, Cyrillic and oriental alike, are invaluable.
Of the 90 (including the partially preserved ones) Cyrillic manuscripts, the oldest ones date from the 13th century: an excerpt from Apostol jevandelja, written on leather, and Psaltir, found in the village of Pecari, near Bela Palanka, in Raška. Among the numerous Cyrillic manuscripts dating from the 14th, 15th, 16th and 17th centuries, the most important ones are Minej za mart-april, dating from 1344-1345, the oldest preserved copy of Pohvale Sv. Simeunu i Sv. Savi by Teodosije, dating from the second half of the 14th century, Cetvorojevandelje, dating from the second part of the 15th century, Dušanov zakonik, a manuscript from Baranja, dating from the beginning of the 16th century, Panagerik, written in 1595 in the Holy Trinity monastery, near Pljevlja, etc.
The greatest part of the collection of oriental manuscripts, which consists of 397 manuscripts in 633 volumes, is taken up by manuscripts in the Arabian (498), Turkish (126) and Persian (9) languages. The oldest manuscript dates from 1206. These manuscripts were mostly written on our territory and most of them deal with matters of law, history, literature, philosophy etc.
Among the oldest printed books from the 15th century (incunabula), it is important to mention Oktoih prvoglasnik and Psaltir sa posledovanjem, printed in Cetinje in 1494. and Biblia latina, printed in Nuremberg in 1477, which were illuminated manually. A very important collection of books dating from the 16th century, srbulje, was printed in Venice, Gracanica, Sebeš, Mileševo, Mrkšina crkva, Skadar, Trgovište and Belgrade. Of these editions, Oktoih, printed in Gracanica in 1539, is especially important. It contains some very rare illustrations – a wood carving of the monastery of Gracanica on the first page. A well-preserved copy of Cetvorojevandelje, printed in Belgrade in 1552, is also very important.
The Library owns many books in foreign languages such as the first edition of Marko Marulic’s works in Latin De institutione bene vivendi printed in Venice in 1506, Chronicorum turcicorum printed in Frankfurt am Main in 1578, containing an etching of the Belgrade fortress, Geography by Ptolemy printed in Venice in 1574, Il regno degli Slavi by Mavro Orbini dating from 1601, the famous Atlas by Mercator, printed in Amsterdam in 1630, which contains a map of Serbia.
Among the numerous books from the 18th century, the following should be mentioned: Stematografija by Hristifor Žefarovic (Vienna, 1741), Bukvar by Zaharije Orfelin, printed in Venice in 1767, Život i prikljucenija by Dositej Obradovic (Leipzig, 1783), Istorija slovenskih naroda by Jovan Rajic (Vienna, 1794), the first Serbian journal – Slaveno-srbski magazin by Zaharije Orfelin, published in Venice in 1768, and the first Serbian newspapers - Slaveno-serbske vjedomosti, printed in Vienna, 1792-1794.
The 19th century collection of books includes: Pjesnarica i Pismenica by Vuk Karadžic (Vienna, 1814), the only preserved original edition of Ustav knjaževstva Serbije, that is, the Sretenje Constitution, published in Kragujevac in 1834, the first editions of works by Ðura Danicic, Branko Radicevic, Petar Petrovic Njegoš, Preradovic, Svetozar Markovic.
Among the serial editions the Library owns: Zabavnik, edited by Dimitrije Davidovic from 1834, Srpske novine from the very first issue, published in Kragujevac in 1834, Novine Serbske issued in Vienna from 1813 and edited by Dimitrije Davidovic and Dimitrije Frušic, Šumadinka, edited by Ljuba Nenadovic in 1850, Danica ilirska, edited in Zagreb by Ljudevit Gaj, etc.
A very valuable archive collection contains letters and documents spanning the period from the end of the 17th century to the 20th century. The largest part of the collection is taken up by personal correspondence of well-known persons. There are about 4.000 letters and 22.000 hand-written pages.
In the advertisement and leaflets collection, one can find important offers for subscription to Serbian books from the first half of the 19th century. The map and atlas collection contains old maps that include those of Serbian territories. The most important ones are the Belgrade plans from the 18th century in copper engravings.