Ego is the self, particularly the individual’s conception of oneself. It is capable to cope with anxiety by rational measures in most instances and if these are not sufficient,however, the ego resorts to irrational protective measures ,such as, rationalization, projection, denial of reality etc. These are referred to as ego-defense mechanisms as these alleviate the painful anxiety by pushing painful ideas out of consciousness and, hence, a distorted view of reality instead of enabling one to deal directly with the problem creates an undesirable schism between actual reality and the individual’s perception of it. That’s why, in the depths of the unconscious mind exist hurtful memories; forbidden desires; and other experiences those that are repressed. As a matter of fact, the individual is unaware of such unconscious material that which remains continue to seek expression and may be reflected in fantasies and dreams,at times, when ego controls are temporarily lowered.If, unconscious material is not brought to surface consciousness and integrated into the ego structure it, invariably, leads to irrational and maladaptive behaviour. Egoistic or egotistic is conceited; motivated primarily by self-interest; or having the tendency to over evaluate the self or one’s own accomplishments. The chief functions of ego are (a) reality testing or learning to distinguish between self and environment; (b) mediating between the demands of the Id and the superego, which embodies the critical and moral aspects of the self. Defense mechanism is any behaviour pattern that protects the psyche from anxiety, shame, or guilt. Some common defense mechanisms are as under: 1.Repression. It is the forceful ejection from consciousness of impulses, memories, or experiences that are painful or shameful and generate a high level of anxiety. 2.Regression. It is a retreating; a moving backward; or a return to earlier levels of development. 3.Projection. Attributing one’s own traits, attitudes or faults to others. 4.Identification. The process of recognition. 5.Fantasy. It is the process of imagining objects or events in terms of imagery. 6.Compensation. The process of engaging in a substitutive behaviour. 7.Sublimation. The unconscious process, in that, the outlet of libido or sex instinct in a more acceptable form. 8. Aggression. Hostile action directed against a person or thing. 9.Denial. Protecting self from unpleasant reality by refusal to perceive or face it. 10.Rationalization. Contrived “explanations” to conceal or disguise unworthy motives. 11.Displacement. Discharging pent-up feelings on objects not dangerous than the people arousing the feelings. 12. Emotional insulation. Withdrawal and passivity. 13.Intellectualization (Isolation). Logic-tight compartments to separate from incompatible attitudes. 14. Undoing. Dispel unacceptable desires or acts. 15. Reaction formation. The development of a personality trait that is the opposite of the original, unconscious or repressed trait.