Psychological evaluation of the weight loss surgery patient is recommended because of the prevalence of psychiatric comorbidities in persons with severe obesity and the behavioral adaptations required for successful surgical outcomes. Although there is currently no national standard for the specific components of these evaluations, there is general agreement in the literature about the objectives and the kinds of assessment methods that are most useful. This paper summarizes the current literature on psychological evaluation of weight loss surgery patients. Methods of assessment relevant to the major behavioral health characteristics of surgical candidates are reviewed, and results from several studies examining weight loss and quality of life outcomes in relation to pre-surgery psychological characteristics are discussed.