This study examines how three features of self-identity, namely, identity importance, identity firmness, and identity discrepancy, are related to adolescent mental health. In Study 1 (N=203), college students designated as the healthy-control group (N=85) demonstrated higher identity firmness and lower identity discrepancy than those designated as the psychosomatic group (N=56). Three multiple regression analyses indicated that identity discrepancy was a better predictor of psychosomatic reactions than identity importance, yet its predictability did not differ from identity firmness. Findings of Study 1 were replicated in Study 2 (N=185). Another group of college students designated as the healthy-control group (N=65) demonstrated higher identity firmness and lower identity discrepancy than those designated as the neurosis group (N=56). Study 2 also indicated that identity discrepancy was a better predictor than identity firmness for almost all of the subscales included in the SCL-90R. The present study concluded that the newly developed concept of identity discrepancy” offers a unique view for understanding adolescent mental health, provided that the individual is not at a state of both low identity importance and low identity firmness.