The authors integrate explorations by Blatt and colleagues of contributions of patient personality, therapeutic relationship, and change in mental representation to sustained therapeutic change. A pretreatment personality characteristic, self-critical perfectionism, a negative self-schema, significantly interfered with therapeutic progress in manual-directed, brief outpatient treatment for depression. The therapeutic relationship, however, facilitated changes in this negative self-representation, leading to sustained therapeutic change. The authors also explored change in the content and structural organization of representations of self and significant others in long-term, intensive inpatient treatment. A detailed clinical example elaborates the processes through which the therapeutic relationship facilitates changes in the thematic content and cognitive structural organization of patients' interpersonal schemas that appear to be the basis for sustained therapeutic gain.