Beck Depression Inventory (BDI) scores of 328 adolescents referred to a depression clinic were factor analyzed to test the discriminant validity of each factor. Three of the four factors (Negative Self Attitude. Performance Difficulty, and Somatic Symptoms) discriminated depressed adolescents from those with a behavior disorder or no diagnosis; the Negative Self Attitude and Performance Difficulty factors also discriminated depressed from anxious adolescents. The fourth factor, Physical Worry, failed to discriminate diagnostic groups. Diagnostic efficiency statistics are reported for both the BDI and for items comprising the 13-item BDI Short Form. Results indicate the BDI is a valid screening tool for adolescent depression in a clinical setting, regardless of the presence of comorbid conditions.