Although the production of structural change in the personality is commonly accepted as a goal of psychoanalytic treatment, there is relatively little mention in the analytic literature of specific criteria by which such change is to be assessed. Attempts have been made to describe the process of structural change as it occurs in psychoanalysis and to differentiate such changes from those occurring in other forms of therapy. Structural change is described as a process occurring throughout the entire course of analysis, but a distinction is made regarding the change in derivative vs. core psychic structures. The ongoing process of assessment of structural change is described, and clinical illustrations of change are presented, in an attempt to illustrate and define the process more accurately.