T4-Gutachter
The T4-Gutachter were medical experts who were employed by the Zentraldienststelle-T4 to organize and carry out the Action T4 "euthanasia" program in Nazi Germany. Based on reporting forms with information about the mentally ill and disabled, they decided who would be the victims killed by gas in "euthanasia" centers. An internal document from the organization T4 shows a list of 40 physicians who were among those who worked for Action T4.
List of Action T4 experts
Copies of the reporting forms were dispatched to three or four of the above experts. The results were sent to the T4-Zentraldienststelle and presented to one of the three Obergutachter, who had the final word.List of Action T4 top experts
List of experts for child euthanasia
There were also three medical experts for the "euthanasia" of children, starting a little before the Action T4 for adults:| Person | Lifespan | Period as expert |
| Werner Catel | 27 June 1894 – 30 April 1961 | From autumn 1939 |
| Hans Heinze | 18 October 1895 – 2 February 1983 | From autumn 1939 |
| Ernst Wentzler | 3 September 1891 – 9 August 1973 | From autumn 1939 |