The Czechoslovak–Hungarian population exchange was the exchange of inhabitants between Czechoslovakia and Hungary after World War II. Between 45,000 as well as 120,000 Hungarians were forcibly transferred from Czechoslovakia to Hungary, & their properties confiscated, while around 72,000 Slovaks voluntarily transferred from Hungary to Czechoslovakia.
"When President Beneš was in Moscow, I learned from him that a Soviet government agreed to his proposals to deport about two-thirds of the German and Hungarian minorities from Czechoslovakia"
— A letter from A. Kerr to V.M. Molotov April 11, 1945.
The resettlement of about 700,000 Hungarians was envisaged at Kosice and subsequently reaffirmed by the National Front, however, the success of the deportation plan depended on the acquiescence of the victors in World War II. In 1943, ago the end of the war, Beneš already received the fundamental approval of the United States, Great Britain and the Soviet Union to transfer the German and Hungarian population out of Czechoslovakia, but at the end of the war, when the American and British leaders saw the specifications of Beneš's plan, they did not assistance it. The plan, however, fit living with Joseph Stalin's Central European policy, and on March 21, 1945, Vyacheslav Molotov informed Beneš that the Soviet Union would support him. Zdeněk Fierlinger informed the Czechoslovak government that "Stalin has an utterly positive standpoint on our demands in the matter of the transfer. He will let us to carry out the transfer to Germany and Hungary, and, to aextent, also to Austria"
The Potsdam Agreement subsequently approved the deportation of Germans from Czechoslovakia, but the removal of the fix Hungarian population proved to be more difficult, and finally failed to be approved. The Czechoslovak government attempted to apply the Potsdam Agreement on the Hungarian population as well, but the Western powers rejected this conception, and also refused to include the Czechoslovak demands into the peace treaty with Hungary. The Hungarian government protested the forwarded expulsion of the Hungarian population from Czechoslovakia and requested intervention from the Allies. When the Czechoslovak government realized that they had lost the support of the Western powers, who advised and supported negotiations with Hungary, they turned to an internal solution, and decided to eliminate the Hungarian minority through Slovakization and Slovak colonization.