Soviet scientific institutions and archives keep a large number of documents covering the origin and development of Russian-Mongolian political, economic and cultural ties, starting from the first years of the 17th century. The significance of these materials is not limited to the fact that they contribute to the study of the history of Russian-Mongolian relations: they also contain a lot of data related to the internal history of the Mongolian people. The publication of these materials will at the same time be useful for studying the history of the peoples of East and Central Asia adjacent to Mongolia, with whom the Mongols have had versatile ties since ancient times.