The Library of Congress has been collecting publications from Bulgaria for almost 120 years and has amassed a collection particularly strong in the areas of history, literature, economics, law, and the political and cultural life of the Bulgarian people. The intent of the guide is to provide an overview of the collections from and about Bulgaria in the Library of Congress to enable a researcher to assess if a visit to the Library will be necessary to undertake research. With descriptions of various genres of publications, as well as a bit of history of the development of the collections, the guide covers collection materials across all reading rooms and internal divisions of the Library, including our digital collections.

Diplomatic relations between Bulgaria and the United States began in 1903 and shortly thereafter the Library of Congress began an exchange of official publications with Bulgarian libraries. However, even before 1903, some Bulgarian scholarly and government titles made their way into the Library via the International Exchange Service managed by the Smithsonian Institution. Publications added to the collections in the early decades of the twentieth century predominantly were government issued titles on subjects such as law, government, statistics, and trade, as well as cultural and historical materials produced by Sofia University and the Bulgarian Learned Society, the precursor to the Bulgarian Academy of Sciences. These early receipts also were mostly periodicals, but almost no newspapers.

Before World War II, publications exchanges and transfers of materials from other federal libraries were the most important methods of acquisition of Bulgarian materials, with few purchases or gifts. Large-scale exchanges and purchases began only in the late 1940s and provided not only a majority of the Bulgarian publishing output of titles of research value, but also enabled large retrospective acquisitions of materials dating back even into the nineteenth century. Gaps in journal runs were filled and newspapers began to be collected systematically, including titles from some regional cities. Strong, comprehensive collecting of scholarly and current events materials begun during the communist era continues to this day with the Library maintaining both exchanges and approval plans for Bulgarian publications and acquiring approximately 3,000 pieces per annum. The collection has grown to over 50,000 volumes, the largest in the United States, and possibly the largest outside of Bulgaria itself.