The Scientific Archive of the National Museum of the History of Ukraine (NA NMIU) contains three letters dated by 07/15/1930, 09/15/1930 and 11/30/1935, addressed to the famous archaelogist of the Crimea Nikolai Ernst (1889—1956), the authors of which are famous archaeologists Boris Zhukov, Lavrenty Moiseev and Petr Efimenko. These letters contain information about excavations, which in 1920’s — 1930’s were carried out in different regions of the Crimean peninsula and are important sources for studying the history of the Crimean archaeological study. Today N. Ernst’s documents, stored in the archives of Simferopol, Kyiv, St. Petersburg and Moscow, are used by researchers who study the archaeological heritage and life of N. Ernst. However, three letters from the NA NMIU have not become the subject of a separate study yet and have not been introduced into scientific circulation. The addressee of these letters, N. Ernst, in 1920’s, worked in the Crimean department for museums and protection of monuments of art and antiquity, was the secretary of the Taurida Society of History, Archaeology and Ethnography, and in April 1930 he headed this Society. These letters contain information about archaeological research in the Crimea, which is not mentioned in the published article by N. Ernst ‘Chronicle of archaeological excavations and exploration in the Crimea for 10 years (1921—1930)’. The letters of B. Zhukov (1930) and L. Moiseev (1930) are probably the answers to the request of N. Ernst, as the head of the Taurida Society of History, Archaeology and Ethnography, send information about the work of local archaeological expeditions for the preparation of a general report. These letters contain information about excavations of archaeological monuments from different historical eras, which are located in different regions of the Crimea and are an important source on the history of the Crimean archaeology of 1920’s — 1930’s. In the third letter, the author of which is P. Efimenko (1935), talks about the participation of N. Ernst in the meeting of the Commission for the Study of Fossil Man, which took place in Leningrad on 20—25th December 1935. The purpose of this meeting was to prepare the Soviet section of INQUA to participate in September 1936 in the III International Conference of the Association for the Study of the Quaternary. Efimenko recommended N. Ernst to prepare a report on the results of the exploration of the Chokurcha Cave.