Treatment-related decreases in Dysfunctional Attitudes Scale (DAS; Weissman & Beck, 1978) scores have been interpreted as evidence that dysfunctional attitudes are state-dependent concomitants of depression. Data from the National Institute of Mental Health Treatment of Depression Collaborative Research Program were used to reexamine the stability of dysfunctional attitudes. Mean scores for Perfectionism, Need for Approval, and total DAS decreased after 16 weeks of treatment. However, test-retest correlations showed that the DAS variables displayed considerable relative stability. Structural equation models demonstrated that dysfunctional attitudes after treatment were significantly predicted by initial level of dysfunctional attitudes as well as by posttreatment depression. The relative stability of dysfunctional attitudes was even higher during the 18-month follow-up period. The results were consistent with Beck's (1967) and Blatt's (1974) theories of vulnerability.