The study, based on original and unused archive materials, aims to describe and analyze the development of the ethnographic department of the National Museum in years 1918-1938, in the context of contemporary ethnographic science and museology transformations as well as socio-political conditions. A separate ethnographic department of the National Museum was established in 1922, when the museum’s existing ethnographic collection was merged with the treasures of the Czechoslavic Ethnographic Museum. This unification was a manifestation of the centralist tendencies of Czech interwar museum management. Another such tendency - strong political influences on cultural institutions - was represented by an unsuccessful attempt to further unite thus created entity with the collections of the Czechoslovak Agricultural Museum. In context of the entire Museum’s development, some interesting features of the department’s development can also be mentioned: under the leadership of Václav Fabian and Drahomíra Stránská, later one of the key figures of Czech interwar ethnography, the department became a pioneer of short-term exhibitions, and a picture archive was an integral part of the ethnographic collection from the very beginning. Certain scientific projects in the department were important in terms of the development of ethnography (an attempt to establish an open-air folk museum), but they also had a significant political aspect (moving the Greek-Catholic church from the Carpatho-Ruthenian town Medvedovce to the Kinský Garden complex).