The current study was conducted to evaluate the overall effectiveness of the Rorschach Comprehensive Systemís (CS) (Exner, 1993) Depression Index (DEPI) and Coping Deficit Index (CDI) in assessing depression among a clinical sample of adolescents. DEPI and CDI archival data collected from roughly 340 inpatient adolescents were compared via independent, pair-wise t-tests with data from Exnerís (1993) non-clinical, CS normative sample of roughly 450 adolescents to investigate degree of co-relationship for both DEPI and CDI by diagnostic group (i.e., clinical depressed, clinical non-depressed, and non-clinical). Pearson coefficients assessed the degree of co-relationship between DEPI and CDI total scores, and ANOVA analyses tested the overall effect of age. Diagnostic efficiency coefficients were calculated for clinical DEPI and CDI scores, and variable combinations based on Exnerís (1993) cutoff points. Also, the incremental validity of the DEPI and CDI towards predicting depression was evaluated using hierarchical logistic regression, relative to the contributions of the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A)(Butcher, Williams, Graham, Archer, Tellegen, Ben-Porath, and Kaemmer, 1992) and the Reynolds Adolescent Depression Scale (RADS)(Reynolds, 1987). For the most part, t-test results revealed no significant differences in DEPI total scores between clinical and non-clinical adolescents, or depressed-only and non-depressed clinical adolescents. Both depressed and non-depressed clinical groups demonstrated significantly higher CDI scores than the non-clinical adolescent group. When DEPI and CDI scores were compared, significant correlations were observed for the depressed-only group and combined depressed and non-depressed clinical adolescents, but not for non-depressed clinical adolescents. No significant main effect of age was identified on either DEPI or CDI total scores. Overall, the DEPI yielded diagnostic efficiency considerably inferior to that anticipated by Ganellenís (1996) roughly comparable study involving adults. Overall, the CDI did not contribute meaningfully towards enhancing the diagnostic efficacy of the DEPI, as Exner (1993) has predicted. Findings provided partial corroboration of Archer and Krishnamurthyís (1997) study in indicating that neither the DEPI nor CDI total scores appeared to produce incremental increases towards improvement in diagnostic classification. Limitations of the current study, implications for the assessment of depression for adolescent populations, and recommendations for future research are discussed.