A number of studies have attempted to identify the factor structure of the Dysfunctional Attitude Scale (DAS). However, no studies have done so using a clinical sample of outpatients likely to generalize to the clinical trials in which the DAS is commonly used. The current investigation utilized exploratory structural equation modeling in an outpatient sample (N = 982) and found support for a one-factor solution (composed of 19 items). This solution was largely confirmed in a second outpatient sample (N = 301). Construct validity was demonstrated in correlations with measures of depression, social interaction anxiety, and symptoms of obsessive-compulsive disorder.