OBJECTIVE:To assess the prevalence of night eating syndrome (NES) and binge eating disorder (BED) and their related behavioral and psychological correlates in persons who sought bariatric surgery. RESEARCH METHODS AND PROCEDURES:A consecutive series of 215 persons with extreme obesity (82% women, 70% European American) completed the Weight and Lifestyle Inventory and a semistructured interview as part of a pre-surgery behavioral/psychological assessment. Diagnoses for NES and BED were based on graded diagnostic criteria. RESULTS:Percentages of participants who met diagnostic criteria for NES by interview were 1.9% for the strictest definition and 8.9% across all definitions of NES. After interview, full DSM-TR criteria for BED were met by 4.2%; an additional 1.4% reported binge eating at least once per week. Self-reported prevalence of NES and BED were higher. Those with NES or BED had significantly more symptoms of depression and a greater history of psychological complications than the remaining sample. DISCUSSION:The prevalence rates of NES and BED among this population of bariatric surgery candidates were lower than expected based on previous reports. Findings and hypotheses regarding lowered prevalence rates are discussed.