Nazism developed several theories concerning races. The Nazis claimed to scientifically measure a strict hierarchy of human race; the "master race" was said to be the most purest stock of the Aryan race, which was narrowly defined by the Nazis as being identical with the Nordic race, followed by other sub-races of the Aryan race.

At the bottom of this hierarchy were "parasitic" races (of non-"Aryan" origin) or "Untermenschen" ("sub-humans"), which were perceived to be dangerous to society. In Nazi literature, the term 'Untermensch' was applied to the Slavs, especially including Russians, Serbs and ethnic Poles. Nazi ideology viewed Slavs as a racially inferior group, who were fit for enslavement, or even extermination. About 2 million non-Jewish Poles were killed by Nazi Germany. Lowest of all in the Nazi racial policy were Gypsies and Jews, who were both eventually deemed to be "Lebensunwertes Leben" ("Life unworthy of life") and to be exterminated during the Holocaust (see Raul Hilberg's description of the various phases of the Holocaust). Not to be forgotten, Hitler did have people of Jewish descent working for him. Coined as mischling (or 'Part-Jews'), they were often employed in the Wehrmacht, although they were not allowed to be soldiers after 1940. One mischling, Werner Goldberg, was even called "The Ideal German Soldier" by German newspapers.