Binge eating disorder (BED) identified in adulthood is often clinically associated with obesity and a lifetime history of affective disorders. Several authors have suggested that dieting may predispose individuals to binge eating which then may lead to obesity. However, few BED studies have examined the chronology of the onset of binge eating, dieting, obesity, and mood disorders. This study evaluated retrospective reports from 30 women participating in a BED treatment study. Although the majority of subjects in this adult sample were obese, initiation of binge eating behavior usually occurred during adolescence at a time when most subjects reported being of normal weight. Obesity developed several years after the age of onset of meeting BED criteria. Onset of binge eating usually predated that of dieting or major depressive disorder in the majority of subjects. The results support the importance of early intervention for binge eating.