Aktion 1005 (Operation 1005) was a code name for the large-scale campaign to destroy all evidence of the mass extermination of European Jewry at the hands of the Nazis. The operation began in June 1942 and lasted until late 1944.

By the summer of 1942, countries in the West had begun receiving reports of the mass murders going on in Europe. This caused the Nazis to try to find a way to conceal the evidence of their horrific activities. In June 1942 SS-Standartenfuehrer Paul Blobel was appointed head of Aktion 1005, and the first corpses were burnt in the Chelmno extermination camp.

The dirty work of Aktion 1005 was carried out mainly by Jewish prisoners. They were forced to dig up the mass graves and remove the corpses. They built pyres made out of long wooden beams, soaked them with flammable liquid, arranged the corpses in layers between the beams, and burnt them. When this was finished, the area was flattened out, plowed, and replanted. After the work was done, the prisoners who had participated were themselves murdered in order to keep the operation secret. In some cases, the Aktion 1005 prisoners tried to escape this fate.

Between the summers of 1942 and 1943, corpses were burnt in Belzec, Treblinka, Sobibor, and Auschwitz. In June 1943 the Germans began burning corpses in the occupied Soviet Union and Poland. Two Sonderkommando prisoner units were organized. One worked in areas such as Berdichev and Zamosc, the other in areas including Riga and Dvinsk. Aktion 1005 was also carried out in Belorussia and the Baltic countries, where the corpses of Soviet prisoners of war were burnt. By mid-1944, Aktion 1005 activities were focused on the Generalgouvernement—a Sonderkommando unit was established in each of its districts. Soon, similar actions were also performed in those parts of Poland annexed to Germany. Aktion 1005 was also carried out in Yugoslavia.

The destruction of the mass graves in Eastern Europe made it difficult to determine the number of victims exterminated by the Nazis, and fueled the flames of Holocaust denial.