In this study, we sought to determine whether changes in narcissism among adolescents; occurred during a 6–month period of treatment for substance abuse and whether level of narcissism was related to progress in treatment and treatment persistence versus withdrawal. Participants were 95 adolescents (M = 16 years of age) entering or already in long-term treatment for drug abuse, surveyed three times over 6 months. Narcissism was measured by two instruments based on Kohut's theory of narcissistic development. Findings indicated that many, but not all, narcissistic characteristics did change during treatment. Theorized relations were found between narcissisc scores and progress in treatment for most narcissistic manifestations. The ability to relinquish angry acting-out behavior distinguished dropouts from persisters.