Background: Binge eating in the obese, specifically those undergoing bariatric surgery, has only recently been investigated. This study is a continuation of a long-term effort to determine the impact of eating disorders on the outcome of bariatric surgery. Methods: Self-report questionnaires (Binge Eating Scale, Beck Depression Inventory, Questionnaire on Weight and Eating Patterns) were completed by 125 patients preparing to undergo gastric bypass surgery. Results: Binge eating was clearly a problem in this population, with 33.3% showing severe binge eating problems on the Binge Eating Scale. Over half of patients engaged in bingeing or grazing, most reporting a frequency of two or more times per week. A high level of depression was associated with binge eating. Conclusions: Because postsurgical long-term weight loss maintenance is contingent on modifying eating behavior, the identification and treatment of such disorders may be critical to successful long-term outcome in these patients.