The mood-state hypothesis proposes that underlying dysfunctional beliefs are more available for therapeutic interventions when patients are in a negative mood state than when they are in a positive mood state. After briefly reviewing evidence supporting the mood-state hypothesis, this article offers recommendations for treating dysfunctional beliefs. First, when patients begin therapy in a clinically depressed state, we recommend working on underlying dysfunctional beliefs early in treatment when the presence of negative mood enhances the patient's ability to report the beliefs. Second, when symptoms have remitted, mood is positive, and underlying beliefs are not readily reported, we discuss four ways to obtain information about the underlying beliefs: direct accessing strategies, the therapeutic relationship, homework, and the case formulation. Finally, when patients experience recurrent pronounced mood shifts, we recommend teaching them to anticipate corresponding shifts in thinking.