Technical Abstract: To determine the prevalence of binge eating disorder (BED) and night eating syndrome (NES) among applicants to the Look AHEAD (Action for Health in Diabetes) study. The Eating Disorders Examination-Questionnaire (EDE-Q) and the Night Eating Questionnaire (NEQ) were used to screen patients. Phone interviews were conducted using the EDE for those who reported at least eight episodes of objective binge eating in the past month and using the Night Eating Syndrome History and Interview for those who scored > or =25 on the NEQ. Recruitment at four sites (Birmingham, n = 200; Houston, n = 259; Minneapolis, n = 182; and Philadelphia, n = 204) yielded 845 participants (58% women; mean age = 60.1 +/- 6.7 years; mean BMI = 36.2 +/- 6.3 kg/m(2)). Screening scores were met by 47 (5.6%) applicants on the EDE-Q and 71 (8.4%) on the NEQ. Of the 85%, (40/47) who completed the EDE interview, 12 were diagnosed with BED, representing 1.4% of the total sample. Of the 72% (51/71) who completed the Night Eating Syndrome History and Interview, 32 were diagnosed with NES, equal to 3.8% of the total sample. Three participants had both BED and NES. Participants with eating disorders were younger, heavier, and reported more eating pathology than those without eating disorders. Among obese adults with type 2 diabetes, NES was reported more frequently than BED, which, in turn, was less common than expected.