The authors used a semistructured clinical interview and a self-report battery of questionnaires to measure key features of the anxiety disorders in a large sample of patients seeking treatment at an outpatient anxiety disorders clinic and in a no mental disorder group. Results were consistent with hierarchical models of anxiety and the anxiety disorders such as the model implicit in American Psychiatric Association (1987, 1994) and trait models positing a trait diathesis common to all the anxiety disorders. A higher order general factor differentiated each of the patient groups from the no mental disorder group. Several lower order factors provided the basis for differentiation among the patient groups. Conclusions regarding the degree to which models predicting a hierarchical structure of anxiety and the anxiety disorders are empirically supported must await replication of these results with additional samples.