A case study of a bipolar patient whose mood changes every 24 hours is described to illustrate the changes in cognitive processing and content during different phases of bipolar disorder. The participant completed a battery of questionnaires and tasks on 4 separate occasions: twice when depressed and twice when manic. Depression tended to be associated with the recall of more general and unpleasant autobiographical memories and greater dependence on others as assessed by self-report and behavioral methods. In contrast, mania tended to be associated with more specific and pleasant autobiographical memories, and antidependence. These preliminary findings set the groundwork for further systematic studies of intraindividual variation in cognitive processing in bipolar disorder. The relevance to future research, theory, and clinical practice are discussed.