The regular transfer of ethnic nationals among nations , authorized according to the Potsdam Conference , proceeded from 25 January 1946 until October 1946 . An estimated 1.6 million " ethnic Germans " ( most of them also had Czech ancestors ; and even Czechs , who spoke mainly German over the last years ) , were deported from Czechoslovakia to the American zone of what would become West Germany . An estimated 800,000 were deported to the Soviet zone ( in what would become East Germany ) . Estimates of casualties related to this expulsion range between 20,000 and 200,000 people , depending on source . Casualties included primarily violent deaths and suicides , rapes , deaths in internment camps and natural causes
Potsdam Conference
Potsdam Conference
Sudeten Germans