The appointment of a new chancellor in 1933 marked the beginning of the Third Reich in Germany. The ideology of the Nazi Party focused on establishing a pure Aryan state characterized by nationalism and racial superiority. Their goals would be achieved through a totalitarian form of government that enforced the subjugation, exclusion, and elimination of those they defined as inferior minorities, particularly Jews, who were depicted as non-human. Implementation of the Nazi ideology required the exclusion of Jewish people and other dissenters, particularly Jewish physicians, from their professions. The exclusion of Jewish physicians, referred to herein as a "Medical Professional Elimination Program," was gradually imposed on other Jewish professions in nations absorbed by the Third Reich, and particularly enforced by incorporated Austria. Why did German and Austrian doctors support the Nazi racial ideology, the removal of Jewish physicians from every possible sphere of influence, and subsequently participate in criminal medical research and experimentation, as well as euthanasia of perceived non-contributors to society, and become involved in refining the effectiveness of the death camps? Was the Medical Professional Elimination Program an opportunistic political concept, or was it part of an entrenched ideology? With these questions in mind, the lives of four key Nazi physicians and two institutions are examined.