In the Collection of Manuscripts formed by donations and legates there are over 1600 units (959 titles of manuscripts). The oldest fragments written in the dalmatian benevantana script date from 10th/11th and 13th century. The oldest manuscript originates from the Benedictine scriptorium in the monastery St. Mary on the island of Mljet. This fragment was preserved in the binding of the incunabulum Summa aurea de virtutibus et vitiis by G. Paraldus, printed in Brescia in 1494, when the book was being prepared for restoration. The content pertains to snake bites. The other beneventan manuscript dates from the 13th century, is of religious character and was purchased at an auction in Sotheby's in London in 2011.
A smaller, but very valuable part of the Manuscript collection can be traced all the way back to the library of the former Jesuit college. It consists of 35 manuscripts among which are particularly interesting Dragomir's Octoechos (an orthodox prayer book) from the 13th or 14 centuries, autographs by Ignatius Georgi, Latin poem De Morte Christi by Damian Beneša and others. There are also autographs by many famous Ragusan poets and scientists, from 16th to 19th century. When it comes to Ragusan Latin poetry, the Dubrovnik Research library is the second largest collection in Croatia (and the world). The Manuscript collection also holds originals of most of the works by Ivo Vojnović. Another significant title is the third volume of the encyclopedic dictionary Vocabolario italiano-illirico-latino by the Ragusan lexicographer Joakim Stulli, later printed by Martecchini press in 1810.
The catalogue of manuscripts of DRL was compiled by Stjepan Kastropil, one of the first Dubrovnik library directors. In 1954. the Croatian Academy of Arts and Sciences published Book 1: Manuscripts in Croatian or Serbian languages, and the catalogue of manuscripts in other languages was published in 1997 by Dubrovnik Libraries as Book 2 of the Manuscripts of the Dubrovnik Research library. Both catalogues have been scanned and can be viewed and searched on the ZDUR digital platform.