In examining individuals with binge eating disorder (BED), we aimed to determine whether their binge eating preceded their first diet or their first diet preceded their binge eating, the age of their first diet, the age of their first binge, and the age when they met DSM-IV criteria for BED. Additionally, we aimed to identify psychological factors that may distinguish the two groups. Method: Eighty-seven individuals with BED (19 men and 68 women) were administered the Eating Disorders Examination, the Structured Clinical Interview for DSM-III-R, and several other measures of psychological functioning and psychiatric disturbance. Results: Forty-five percent of the subjects reported that dieting preceded their first binge episode (dietfirst) and 55% reported that binge eating preceded their first diet (bingefirst). There were no significant differences in current eating disturbance, body mass index (BMI), or age for these two groups, but they differed on the age of the first episode of binge eating and the age when binging met BED criteria. The group reporting having binged first had a younger age of onset of binge eating and a younger age at which binge eating met diagnostic criteria than the dietfirst group. The bingefirst group also had a history of more psychiatric problems and were more likely to have an Axis II personality disorder. Discussion: Age of onset of the first binge and BED is markedly different depending on whether an individual began dieting or binging first. These findings suggest that there may be important etiological differences between individuals who binge first and those who diet first. Moreover, individuals who binge first may be at greater risk for psychiatric disturbance. © 1997 by John Wiley & Sons, Inc.