The Jewish community of Warsaw was the largest in Europe. With a population of more than 375,000 it constituted about 30 percent of the city's total population. The Germans occupied Warsaw on 29 September 1939. Two months later they ordered all Jews to wear a white armband with a blue Star of David, Jewish schools were closed, Jewish-owned property was confiscated, and Jewish men were taken for forced labor. On 12 October 1940, the Germans decreed the establishment of a ghetto. Hundreds of thousands of Jews had to move into the designated area; the ghetto was sealed off in November 1940 and surrounded by a 10-feet-wall. Jews from nearby towns were brought to the crowded ghetto, and its population rose to some 445,000. The crowded conditions and the much reduced food allotments to the isolated ghetto soon resulted in starvation and epidemics. 83,000 Jews died between 1940 and mid-1942. From 22 July until 12 September 1942, 265,000 Jews were deported from the Warsaw ghetto to Treblinka extermination camp. In January 1943 the Germans wanted to renew the deportations, but the underground in the ghetto put up resistance and after 6,000 Jews were deported, the plan was aborted. On 19 April 1943, the Germans began liquidating the ghetto. The ghetto inhabitants offered organized resistance inflicting casualties on the well-armed SS and police units. It took four weeks to put down the resistance and deport all the remaining Jews. Perhaps as many as 20,000 Warsaw Jews continued to live in hiding on the so-called Aryan side of Warsaw after the liquidation of the ghetto.
On 1 August 1944, when the front was nearing, the Polish Home Army (Armia Krajowa), rose against the German occupation authorities. The Soviets failed to intervene, and the Germans brutally crushed the revolt that lasted for two months. About 16,000 – 20,000 Polish resistance fighters were killed and around 150,000 civilians lost their lives, among them Jews who had been hiding with Poles after the liquidation of the ghetto; the city center and other parts of Warsaw were razed to the ground; and most of the remaining population was deported to camps or evicted from the city. When the Soviet Army liberated Warsaw on 17 January 1945, were some 300 Jews were found in hiding.