- 27 April – Following a number of inspections at various sites, Heinrich Himmler, Commander of the SS, gives out the order to establish a concentration camp in the former artillery barracks in Oświęcim, known at the time as Auschwitz.
- 14 June – German authorities direct the first transport of political prisoners to Auschwitz – 728 Poles, including a small group of Polish Jews. This day is recognized as the day the camp started functioning. In the period 1940-1945 about 405,000 prisoners are registered at the camp, of which 270,000 were men.
- 19 June – First relocation of local people in order to prevent them from witnessing the crimes, contacting prisoners and helping them escape. The next waves of relocation were connected with plans to develop Auschwitz. In total, the Germans moved at least 5,000 Poles from Oświęcim and its nearby villages. In addition, they deported to nearby ghettos the entire Jewish population of Oświęcim (approx. 7,000). Eight villages are destroyed and more than a hundred buildings demolished, located in Oświęcim and the direct vicinity of the camp.
- 6 July – First prisoner, Tadeusz Wiejowski, escapes. Throughout the history of the camp, out of a total of more than one million deportees, a few hundred prisoners attempt to escape. These were mainly Poles, Soviets and Jews. About 150 prisoners managed to escape. The vast majority of those who failed were shot by the Germans whilst escaping or stopped and later murdered.
- Autumn – Polish resistance informs the Polish Government in exile in London about the camp.
- 22 November – The first execution through firing squad. 40 Poles were executed.