Teaching : between idealisation and principle of reality The author analyses some psychic mechanisms which lead to exercise the teaching occupation. The first part of this article will deal with the notion of idealization of parental images or their substitutes, such as teachers of the elementary school, and the notion of principle of reality as a dynamic allowing the adjustment of the subject to his professional “choice”. Last, a case study will be presented to show how the choice of the teacher’s job can be interpreted as a compromise to approach the parental ideal. The test of reality articulated with the mechanism of sublimation leads the subject to reshape his ideals and his professional choices in order to restore his narcissism.