The authors examined the amount and durability of change in the cognitive content of 156 adult outpatients with recurrent major depressive disorder after treatment with cognitive therapy. The pre-post magnitude of change was large for the Attributional Style Questionnaire Failure composite (d = 0.79), Dysfunctional Attitudes Scale (d = 1.05), and Self-Efficacy Scale (d = 0.83), and small for the Attributional Style Questionnaire Success composite (d = 0.30). Changes in cognitive content were clinically significant, as defined by their 64%-87% scores overlapping with score distributions from community dwellers. Improvement was durable over a 2-year follow-up. Changes in negative cognitive content could be detected early and distinguished responders from nonresponders. In responders, continuation-phase cognitive therapy was associated with further improvements on only 1 measure of cognitive content. Early changes in negative cognitive content did not predict later changes in depressive symptoms, which the authors discuss in the context of methodological challenges and the cognitive theory of depression.