This paper reports a case study in which the authors analyze the application of the debate technique in cognitive restructuring so as to obtain a deeper understanding of the relevant behavioral processes. The authors examined the recordings of a clinical case of low mood disorder and selected five debates that dealt with the same problem. After their transcription, the authors analyzed the client-therapist verbal interaction. Results show changes in the verbalizations of both parties as the treatment progresses. The authors propose a new explanation of these changes, constituting a step forward in the theoretical explanation of the debate technique within the cognitive-behavioral approach.