The goal of the study was to contribute empirical data to the discussion of appropriate diagnostic classification of obese and nonobese, hinging, and nonbinging eating disordered patients. The study consists of two parts: (1) patients with binge eating disorder (BED) (N = 22) are compared to a matched sample of patients with bulimia nervosa (BN) and to 16 patients with obesity (body mass index [BMI] >30). These patient groups were crosssectionally assessed using expert ratings (interview) and self-ratings. (2) A sample of 68 patients with BED were assessed longitudinally on admission and discharge of inpatient treatment and at a 3-year follow-up using the same instruments as in the first study. The study is the first to report longitudinal data on patients with BED. The general pattern of the cross-sectional data was that patients with BN not only had higher scores concerning disturbances of eating behavior and attitude but also for general psychopathology when compared to patients with obesity without marked binges. The scores of patients with BED had an intermediate position between BN and obesity but were closer to BN than to obesity. The BED group (and the obesity group) showed a high degree of body dissatisfaction, which, however, was accounted for by their high body weight. Concerning general psychopathology BED as well as BN had significantly higher scores than the obesity group in the Hopkin's Symptom Checklist (SCL) subscale anger and hostility, in the Complaint List, the PERI Demoralization Scale, and the Beck Depression Inventory. Results of the longitudinal study with BED showed marked improvement in specific and general psychopathology over time. Except for body weight this improvement largely persisted over the 3-year follow-up period. Severity of depression did not predict the course of body weight over time. Data are presented concerning the design of diagnostic criteria for eating disturbed patients not fitting criteria for BN or anorexia nervosa (AN). Arguments pro and contra the introduction of a new BED category in psychiatric diagnostic criteria are discussed. Although there is generally a need for developing or revising the diagnostic criteria for recurrent bingers, our data do not support inclusion of BED (as presently defined) as a separate diagnostic category in DSM-IV. © 1993 by John Wiley & Sons, Inc.