For the plight of Poles who remained in the Soviet interior until the defeat of Germany , see Polish population transfers ( 1944 – 46 ) and the population exchange between Poland and Soviet Ukraine . As the new border between the postwar Poland and the Soviet Union along the Curzon Line ( requested by Stalin at Yalta ) has been ratified , the ensuing population exchange affected about 1.1 million Poles and Polish Jews as well as close to half a million ethnic Ukrainians . According to official data , during the state-controlled expulsion between 1945 and 1946 , less than 50 % of Poles who registered for population transfer were given the chance to leave the westernmost republics of the Soviet Union . The next transfer took place after Stalin 's death in 195559
Yalta
Yalta Conference
Evacuation of Polish civilians from the USSR in World War II