ENThe article presents 15th–19th c. Slavic book collection (ca. 850 volumes) of the National Library of Bulgaria. The oldest preserved Cyrillic publications in the collection are 5 incunabula. Most of the collection’s 16th c. Cyrillic items were published in printing houses of Venice, the rest - in various printing houses of Balkans and Romania. For the history of Bulgaria, the most important are items in ancient Bulgarian language. Among 18th–19th c. Cyrillic books, majority were produced in East Slavic printing houses of Moscow, Kiev, and Vilnius. Although, these items are printed outside Bulgaria, for the Bulgarian historians they are important as they provide information on cultural relations between Bulgaria and other Slavic countries.