On 12 July 1929, governorates and uyezds were abolished, and Demidovsky District with the administrative center in Demidov was established. The district belonged to Smolensk Okrug of Western Oblast. On August 1, 1930 the okrugs were abolished, and the districts were subordinated directly to the oblast. On 27 September 1937 Western Oblast was abolished and split between Oryol and Smolensk Oblasts. Demidovsky District was transferred to Smolensk Oblast. Between 1941 and September 1943, during WWII, the district was occupied by German troops.