The district was reformed by the decision of October 11, 1939 specifically for the occupation of Bessarabia after the Soviet Union signed Molotov–Ribbentrop Pact. At that time its territory included the newly created Moldovian SSR, six oblasts of the Ukrainian SSR (Izmail, Odessa, Dnipropetrovsk, Zaporizhia, Mykolaiv, Kirovohrad) and also the Crimean Autonomous Soviet Socialist Republic as part of the Russian SFSR. The Odessa MD was reinforced by several units from the Ukrainian Front that took part in the Soviet invasion of Poland and Romania, previously formed on base of the Odessa Army Group of the "Kiev Special Military District" (reformed Kiev Military District).