The article considers the process of accumulation, recording, keeping and use of the documentary monuments created on the Belarusian land, from ancient times to the present. It is noted that the regulatory and legal framework that existed in the Grand Duchy of Lithuania in the form of the “archival articles” of statutes, the Sejm resolutions and constitutions contributed to the preservation of documents, primarily of a legal nature. The magnates and gentry of the Grand Duchy of Lithuania took care of their family archives, inviting specialists who were experts in archives to organize them. With the inclusion of the Belarusian lands into the Russian Empire, the local administration was initially indifferent to the preservation of the archives of the Grand Duchy of Lithuania, using them only as a means to fight political and ideological opponents. That was particularly evident in the case of the Vilna Museum of Antiquities with the attached Archaeological Commission – the museum suffered detriment as the administration considered its activities to be “polonophile”. One of the reasons for the closure of the museum and the commission in 1864 was the publication of the collections of documents that did not fit into the official historiographical paradigm. On the basis of the museum, the Vilna Public Library, loyal to the administration, was created with the Manuscripts Department, which began to be completed with the documents and materials found both on the territory of the Lithuanian and mainly Belarusian provinces, and it caused an outflow of documentary monuments from the places of their origin. The Vitebsk Scientific Archival Commission, founded in 1909, played a positive role in the collection and preservation of the documentary monuments in the region; the Commission contributed to the formation of the archives, museum and the library, which, after 1917, acquired the status of the institutions of a provincial level. With the creation in 1922 of the archival service of the republic, the formation of a network of state archives, libraries and museums, the issue of distributing archival documents and materials between them acquires particular urgency. It was discussed at the Second Meeting of Archival Workers of Belarus in December 1927, and also at the meeting of the representatives of archival, museum and library institutions in December 1929. Belarusian archivists D.I. Dovgiallo, M.V. Meleshko and others took part in the discussions on the interaction of archives, museums and libraries in collecting and keeping the archival materials. Currently, the republican museums and libraries keep about 10% of the National Archival Funds of Belarus. On April 18, 2022, the Law of the Republic of Belarus “On the Amendments to the Law ‘On Archives and Records Management in the Republic of Belarus’” was adopted, according to which the right to permanently keep the documents of the state part of the National Archival Funds of the Republic of Belarus was only granted to the state archives, while previously, along with archives, museums and libraries had the right to keep such documents. In the context of the “digital revolution” taking place in the world, the issue of interaction between archival, museum and library institutions in the preservation and use of documents and materials is of particular relevance