Investigators are persistently aiming to clarify structural relationships among the emotional disorders in efforts to improve diagnostic classification. The high co-occurrence of anxiety and mood disorders, however, has led investigators to portray the current structure of anxiety and depression in the "Diagnostic and Statistical Manual of Mental Disorders" ("DSM-IV", APA 2000) as more descriptive than empirical. This study assesses various structural models in a clinical sample of youths with emotional disorders. Three a priori factor models were tested, and the model that provided the best fit to the data showed the dimensions of anxiety and mood disorders to be hierarchically organized within a single, higher-order factor. This supports the prevailing view that the co-occurrence of anxiety and mood disorders in children is in part due to a common vulnerability (e.g., negative affectivity). Depression and generalized anxiety loaded more highly onto the higher-order factor than the other disorders, a possible explanation for the particularly high rates of comorbidity between the two. Implications for the taxonomy and treatment of mood and anxiety disorders for children and adolescents are discussed.