The ego is not an instance that starts to exist suddenly, is a construction. The same if form in the sequncia of identifications the external objects that are incorporated it. He is a mediator, being able, on the other hand, to be considered as a gradual differentiation of id that it leads to a continuous increase of the control on the remaining portion of the psychic device. Therefore, the ego is the defensive polar region of the psiquismo. It is not equivalent to the conscientious one, not if it sets to the conscientious one nor if it confuses with it. Ego has roots in unconscious, as it is the case of the mechanisms of defense, that are functions of the ego, as well as the development of the anguish. The function of the ego is mediating, integrator and humanizadora between the pulses, the requirements and threats of superego and the demands of the exterior reality. In contrast of id that it is broken up in independent trends between itself, the ego appears as a unit and with psychic instance that assures the identity of the person. The mechanisms of defense of the Ego are subconscious processes developed by the personality, which makes possible the mind to develop a solution for conflicts, aggressive, ressentimentos ansiedades, hostilities, impulses and frustrations not solved to the level of the conscience. Psychological technique to develop the personality, its affinity is to try to defend themselves, to establish commitments between conflicting impulses and to alliviate internal tensions selected and operating Freud automatically unconsciously declared that the prohibited term would have to be used ' ' for all the techniques that the ego uses in conflicts that can lead to neurose' '.